Airbag generator, deflector member, coolant/filter means support member, coolant, and housing

ABSTRACT

The invention provided a gas generator for an air bag having any of the following members. A deflecting member is provided to suppress discharge of a combustion product generated by a combustion of gas generating means, and is formed as a tube portion to be capable of shielding a gas discharge port formed at least on a circumferential wall of a housing from the inside of the housing. A coolant/filter means supporting member can position a coolant/filter means, prevent a short pass of an operating gas, and functions as a buffer member between the coolant/filter and the housing, and/or prevent a heat from being transferred to a diffuser shell, and comprises an annular portion arranged to face an end surface of the housing and a wall portion contacting with an inner periphery of the coolant/filter means. Further, in order to make it possible to securely support and fix the coolant means and prevent the short pass of the operating gas, an outer peripheral edge of an end portion thereof is adhered and/or supported to a bent portion or a step portion formed in an inner surface of an upper end surface and/or an inner surface of a lower end portion in the housing. The coolant/filter means is formed in a cylindrical shape obtained by laminating a wire mesh. The housing for the gas generator securely fixes an igniter included in an ignition means, is preferably used at a time of manufacturing a gas generator having a restricted overall height, and has an opening portion for inserting and fixing the igniter or an igniter supporting member. The opening portion is provided with a connecting portion for fixing the inserted igniter or igniter supporting member, and the connecting portion is provided in inner side of the housing rather than the end surface having the opening portion.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/JP01/01258 which has an Internationalfiling date of Feb. 21, 2001, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a gas generator for an air bagprotecting a passenger from the impact. Further, the present inventionrelates to a constituting member used for the purpose of removing acombustion product generated due to a combustion, particularly of gasgenerating means, specifically, (1) a deflecting member, (2) acoolant/filter means supporting member and (3) a housing preventing ashort pass. Further, the present invention relates to (4) a coolant madeof a wire mesh. Further, the present invention relates a (5) a housingin which an igniter inlet also has a bent portion.

In addition, the present invention relates to a gas generator for an airbag using the above and an air bag apparatus.

PRIOR ART

In various kinds of vehicles mainly including a automobile, an air bagsystem is mounted for the purpose of supporting an passenger with an airbag (bag body) quickly inflated with a gas, at a time when the vehicleis collided at a high speed, so as to prevent the passenger fromcrashing into a hard portion inside the vehicle such as a steeringwheel, a windshield due to an inertia, and getting injured. In general,the air bag apparatus comprises a sensor, a control unit, a pad moduleand the like, and the pad module comprises a module case, an air bag, agas generator and the like, and is mounted to, for example, a steeringwheel.

Among them, the gas generator is formed so that, when an ignition meansis activated due to the impact, a gas generating means is burnt togenerate a high-temperature and high-pressure gas, and the generated gasis ejected into the air bag (bag body) through a gas discharge port toinflate the air bag, thereby forming a cushion for absorbing the impactbetween a steering wheel and the passenger. It is known that anoperating gas, which is generated by the combustion of the gasgenerating means for inflating the air bag, generally has ahigh-temperature, and a combustion by-product is included in theoperating gas in some kinds of gas generating means.

Accordingly, in the currently provided gas generator, filter means orcoolant/filter means for purifying the combustion product contained inthe operating gas before being discharged from the housing is disposedin the housing.

However, since the conventionally provided filter means or thecoolant/filter means is generally made of a wire mesh, a solidcombustion product can be removed from the operating gas, but acombustion product generated in a state of fluidized body or asemi-fluidized body cannot be removed. In addition, in the case that thegas generating means generates an alkali mist due to the combustion,there is a possibility such that the alkali mist newly generateshigh-temperature heat particles due to erosions including a chemicalreaction with a filter means, a coolant means or the like which is madeof a stainless steel and widely used, and that these high-temperatureheat particles are discharged out of the housing.

Further, in the conventionally provided gas generator, a cylindricallyformed filter means or coolant/filter means is disposed in the housingfor the purpose of purifying the combustion product contained in theoperating gas and cooling the operating gas before being discharged fromthe housing.

Further, since the cylindrical filter means or the like is for purifyingand/or cooling the operating gas generated due to the combustion of agas generating agent before discharging from the gas discharge port, thegas generating means is stored in a hollow portion of the cylindricalfilter means or the like. Accordingly, the filter means or thecoolant/filter means has a function of defining a space foraccommodating the gas generating means.

Therefore, conventionally in any gas generator in which the gasgenerating means to generate the operating gas due to the combustion ofthe gas generating means, the filter means or the coolant/filter meanshaving the function mentioned above is used in general. It is desirablethat the coolant/filter means does not move in view of forming theaccommodating space for the gas generating means, and that thecoolant/filter means does not move when the operating gas passes.Accordingly, in general, the coolant/filter is disposed by being fixedwith various kinds of methods such as interposing this by upper andlower inner surfaces in the housing or the like.

However, in view of a performance of the coolant/filter means inmanufacturing and activating the gas generator, it is yet insufficientto simply fix inside the housing, and it is desirable to solve variouskinds of problems caused by actions of the coolant/filter means.

In other words, in view of safety in activating the air bag system,desirably, all of the operating gas passes through the coolant/filtermeans, and also in view of the fact that the coolant/filter means isused for forming a space for accommodating the gas generating means at atime of manufacturing the gas generator, desirably, a disposing positionthereof is always fixed. Further, at a time of activating the gasgenerator, there is a possibility such that the housing may have ahigh-temperature by some kinds of gas generating agent or the like andthat the air bag being in contact therewith may be damaged. Therefore,desirably, the heat generated in the above gas generator is nottransferred to at least the housing in the gas discharge port side.Further, at a time of fixing the coolant/filter means to the inside ofthe housing, it is desirable to securely perform fixing.

However, as mentioned above, the above effects cannot be expected onlyby simply fixing the coolant/filter means to the inside of the housing.

On the contrary, the operating gas passing through the coolant means isthereafter will be discharged from the gas discharge port formed in thehousing, however, in view of an effective use of the coolant means, itis desirable to prevent the operating gas from passing through thecoolant means disposed around the gas discharge port.

Further, an outer shell container of the gas generator is conventionallyformed by casting, forging or press-molding various kinds of metals,however, it is desirable to facilitate manufacturing with a sufficientstrength secured.

Yet, conventional gas generators have to be improved a lot in amanufacturing cost, a manufacturing process, a safety in operation andthe like, with respect to a combination of the coolant means and thehousing.

That is, since the coolant means receives the pressure due to thepassage of the operating gas, fixing thereof needs to be performedsecurely, and at manufacturing the gas generator, in view of the factthat the coolant means is also used for defining the space foraccommodating the gas generating means, desirably the disposing positionthereof is constantly fixed. In addition, in view of safety inactivating the air bag system, it is desirable that the entire operatinggas passes through the coolant means.

Further, in view of a manufacturing process and a manufacturing cost, afurther simple structure with the above functions is desirable.

In conventional gas generators for the air bag, as the coolant and/orthe filter mentioned above, there is used a coolant mainly for purifyingthe operating gas and a filter mainly for cooling the operating gas areused together, or a coolant/filter having a gap structure obtained bycompressing a laminated wire mesh body for simultaneously cooling andpurifying the operating gas. However, in the case of using the coolantand the filter together, a accommodating space therefor is required, andtwo members are formed, so that the container has to be totally larger,and the manufacturing process and the manufacturing cost are increased.Further, in the case of using the coolant/filter, this has both of acooling function and a purifying function of the operating gas, so thatthe accommodating space can be reduced, however, a manufacturing processfor forming the coolant/filter becomes complicated.

Accordingly, in the gas generator for the air bag, with respect to thecoolant and the filter disposed in the housing for the purpose ofcooling and purifying the operating gas, a development has beenperformed in view of the functions, but a development in view offacilitating the manufacture and the manufacturing cost are not yetsufficiently achieved.

In the gas generator formed in this manner, the ignition means includingthe igniter is disposed in the housing as a requisite member forstarting an activation of the gas generator, and the igniter iselectrically connected to a control unit arranged out of the housing.The control unit has a function of receiving a signal from a sensordetecting the impact so as to judge a degree of the impact and then,outputting the activating signal. Accordingly, at a time of disposingthe igniter, in order to receive the activating signal from the controlunit, a portion electrically connected to the control unit is exposedfrom the housing.

Therefore, in the conventionally provided gas generator for the air bag,an opening portion for receiving and fixing the igniter is formed in thehousing, and an edge of the opening portion is formed so as to protrudein a cylindrical shape towards the outside of the housing.

However, since the gas generator for the air bag structured in the abovemanner is stored in a module case together with the air bag (bag body)or the like, and the module case is mounted in a steering at a driverside and in a dashboard before a front passenger (but not a driver)side, it is desirable to make the module case smaller. In particular, inthe case of arranging in the driver side, since a height of the gasgenerator reflects directly on a thickness of the steering wheel, it anassignment to restrict an total axial length of the housing to be small.

DISCLOSURE OF THE INVENTION

The present invention relates to a constituting member used for thepurpose of removing a combustion product, in particular, (1) adeflecting member, (2) a coolant/filter means supporting member, (3) ahousing having a structure preventing a short pass, and (4) a coolantmade of a laminated wire mesh. Further, the present invention relates a(5) a housing in which an igniter inlet also has a bent portion.Further, the present invention relates to a gas generator for an air bagusing the above and an air bag apparatus.

The present invention relates to a gas generator using at least one ofthese constituting members, and an air bag apparatus, and someconstituting members may be combined.

Further, the present invention relates to a method of restricting andcontrolling a gas flow-path by the aspects (1), (2), (3) or the like soas to prevent a combustion residue or the like from flowing out andavoid an influence of an abnormal combustion gas such as a flame or thelike, thereby obtaining a desirable gas outflow.

A description will be given of respective members below.

(1) Deflecting Member

The present invention provides a constituting member which solves theproblems of the conventional art mentioned above and makes a combustionproduct be contained in an operating gas discharged from a gas dischargeport as little as possible while being formed in a simple structure, anda gas generator for an air bag effectively using the same.

A deflecting member according to the present invention is used forremoving a combustion product contained in an operating gas afterpassing through a coolant/filter means, which is the product producedfrom a gas generating means provided in a housing.

In other words, the deflecting member of the present invention is aconstituting member used for a gas generator for an air bag comprising,in a housing with a gas discharge port, a gas generating means togenerate an operating gas for inflating an air bag and a cylindricalcoolant/filter means to cool and/or purify the operating gas in thehousing, and the deflecting member is provided with a tube portion insuch a shape to be arranged to face the inner periphery of the housingof the cylindrical gas generator, and the tube member has a shape and/ora structure to be able to, at least, shield the gas discharge port,which is formed in the circumferential wall of the gas-generatorhousing, from the inside of the housing.

It is desirable that the above deflecting member, in case of beingdisposed in the housing, is formed in a shape and/or a structure suchthat a combustion product generated due to a combustion of the gasgenerating means is prevented from being discharged out of the housingfrom the gas discharge port and also a flame of the ignition means forigniting the gas generating means is prevented from being discharged outof the housing from the gas discharge port.

For example, the deflecting member can adhere a fluidized orsemi-fluidized combustion product contained in the operating gas toremove by allowing the operating gas, which has passed through thecoolant/filter means toward the gas discharge port, to strike againstthe tube portion which is disposed in the gas-generator housing and hasa shape capable of being arranged to face the inner periphery of thegas-generator housing.

Accordingly, it is necessary that the tube portion included in thedeflecting member is formed in a shape and/or a structure capable ofshielding a gas discharge port formed on a circumferential wall of thegas-generator housing from the inside of the housing, or in a shapeand/or a structure to cover the part of the coolant/filter projectedhorizontally from a gas discharge port, in the case of arranging thedeflecting member within the housing. By forming the tube portion insuch a shape (including a length)/a structure, in a state of being usedin the gas generator, the operating gas which has passed through thecoolant/filter means strikes against the tube portion before reachingthe gas discharge port, and a flow thereof is deflected. When theoperating gas which has passed through the coolant/filter means strikesagainst the tube portion of the deflecting member, the combustionproduct contained the gas adheres to the tube portion, or is accumulatedin the housing by striking against the deflecting member, thereby beingkept inside the housing. Accordingly, it is possible to prevent a solidmaterial from being discharged through the gas discharge port and tosecurely avoid a damage to the air bag.

An example of such a deflecting member can comprise the tube portionformed in the above manner and an inwardly flange-shaped annularportion, integrally formed with the tube portion. In this case, it isdesirable that the annular portion is formed so as to contact witheither end surface of the coolant/filter means provided in the housing.

And desirably, the above deflecting member in a state of being disposedin the housing has the tube portion formed so that a gap for a flow-passof the operating gas is secured between the coolant/filter means and theinner periphery of the housing. In other words, it is desirable that aninner diameter of the tube portion is partly formed larger than an outerdiameter of the coolant/filter means of the gas generator in which thedeflecting member is used but smaller than an inner diameter of thehousing periphery. For example, this can be realized by forming theinner diameter of an upper portion of the tube portion to be equal tothe outer diameter of the coolant/filter means as well as by forming theinner diameters of a middle portion and a lower portion thereof to belarger than the inner diameter of the upper portion but smaller than theinner diameter of the housing periphery.

As mentioned above, the deflecting member is for removing the combustionproduct contained in the operating gas by allowing the gas to strikeagainst the tube portion. Therefore, desirably, the deflecting member isformed not to be bent due to a pressure of the operating gas nor toclose the gas discharge port. This can be materialized, for example, byforming a supporting portion with an end thereof bent outwardly andradially on the lower end of the tube portion. In this case, thesupporting portion contacts with the inner periphery of the housing tosupport the tube portion, whereby making it possible to stop the tubeportion from expanding due to the pressure of the operating gas. When aflange-shaped supporting portion is formed in a lower end of the tubeportion, it is desirable to form a ventilating portion in the supportingportion which is capable of letting the operating gas pass through. Sucha ventilating portion can be realized by forming a plurality ofthrough-holes in the supporting portion or notching a peripheral edgethereof partly or entirely in a serration shape or a gear shape.

The above deflecting member can be also used as a mist collecting memberfor collecting a combustion by-product generated by the combustion ofthe gas generating means, that is, a semi-fluidized or solid mist, andfurther can be used as a flame-preventing plate capable of preventing aflame, which is generated by the combustion of the ignition means or thegas generating means, from being discharged out of the housing throughthe gas discharge port.

In the case that the inwardly flange-shaped annular portion, whichcontacts with either of end surfaces of the coolant/filter means, isprovided in the tube portion of the deflecting member, it is possible toposition the deflecting member at a time of arrangement by controllingan inner diameter of a central opening of the annular portion andbringing the inner-edge surface into contact with the end surface of theinner cylindrical member disposed in the gas-generator housing. Forexample, when a welding margin in a flange shape is formed on the innercylindrical member and the welding margin is welded to an inner surfaceof a diffuser shell, it is desirable that the inner diameter of thecentral opening of the annular portion is formed to correspond to theouter diameter of the welding margin. Further, by forming the tubeportion to join an outer peripheral edge of the inwardly flange-shapedannular portion, a position of the coolant/filter means can bedetermined by a curved portion between the tube portion and the annularportion, and can be prevented a so-called short pass such that theoperating gas passes between the end surface of the coolant/filter meansand the inner periphery of the housing at actuation of the gasgenerator. This can be also realized, for example, by supporting theouter peripheral edge of the cylindrical coolant/filter means which isdisposed in the housing with the curved portion as well as by clingingthereto and contacting therewith.

In the case of forming this annular portion to have a proper elasticityat least in the thickness direction thereof, the coolant/filter meanscan be held securely due to an elasticity of the annular portion. Forexample, the annular portion can be made of an elastic member such as aresin, or can be bent so as to be formed in a shape or a structurecapable of achieving a proper elasticity. Further, by forming theannular portion so as to achieve a proper heat insulating effect, theheat of the coolant/filter means, which is increased by cooling theoperating gas, can be inhibited from transferring to the diffuser shell,and therefore a damage to the air bag can be avoided. For example, theannular portion can be formed to secure a space for insulating heat byforming, at least, a portion thereof in the coolant/filter side with aheat-insulating member such as a resin, or by bending the portion.

In addition, it is desirable to form, in the annular portion, a wallportion having a shape to contact with the inner periphery of thecoolant/filter means to decide a position of the coolant/filter meanswith the wall portion or to prevent a so-called short pass such that theoperating gas passes between the end surface of the coolant/filter meansand the inner periphery of the housing. In this case, a width betweenthe wall portion and the tube portion is desirably formed to be equal toa thickness of the coolant/filter means provided in the gas-generatorhousing. When the width between the wall portion and the tube portion isadjusted in the above manner, the coolant/filter means can be heldbetween both of the portions, whereby making it possible to securelyposition and fix the coolant/filter means by the deflecting member andto securely prevent the short pass.

As described above, the deflecting member comprising the tube portion,the inwardly flange-shaped annular portion, and/or the wall portionformed on the annular portion can be a single member. In this case, thedeflecting member can be formed, for example, by press-molding astainless steel or the like. If the deflecting member is formed as thesingle member, by forming and providing only one member at time ofmanufacturing a gas generator for an air bag, such functions as toprevent the short pass of the operating gas, to purify the operating gasand/or to position and support the coolant/filter means can be providedat the same time, whereby making it possible to widely reduce themanufacturing cost.

Further, the present invention also provides a gas generator for an airbag including the above deflecting member. In this gas generator, thecombustion product contained in the operating gas can be removedunfailingly.

That is, there is provided a gas generator for an air bag comprising, ina cylindrical housing with a gas discharge port, an ignition means toactivate a gas generator, a gas generating means to generate anoperating gas for inflating an air bag on activation of the ignitionmeans, and a cylindrical coolant/filter means for purifying and/orcooling the operating gas, in which a space portion as a flow path ofthe operating gas is secured between an outer periphery of thecylindrical coolant/filter means and an inner periphery of acircumferential wall portion of the housing, and a deflecting member,which has a shape and/or a structure to deflect a flow of the operatinggas passing through the coolant/filter means towards the gas dischargeport is arranged in the space portion.

Further, the present invention also provides a gas generator in which amist collecting member, for collecting a combustion by-product generatedby the combustion of the gas generating means, that is, fluidized,semi-fluidized or solid mists, is arranged between the outer peripheryof the cylindrical coolant/filter means and the inner periphery of acircumferential wall portion of the housing, and further provides a gasgenerator in which a flame-preventing plate, for preventing a flamegenerated by the combustion of the ignition means or the gas generatingmeans from being discharged out of the housing through the gas dischargeport, is arranged.

It is desirable that above the deflecting member is arranged to contactwith either end surface of the cylindrical coolant/filter means, andfurther, it is desirable that a space portion as a flow-path of theoperating gas is secured between the outer periphery of the cylindricalcoolant/filter means and the inner periphery of the circumferential wallportion of the housing in order to arrange a part of the deflectingmember, and that a portion existing in the space portion is formed andarranged to deflect a flow of the operating gas passing through thecoolant/filter means towards the gas discharge port. Preferably, aportion existing in the space of the deflecting member is formed toinclude a portion which is in contact neither with the coolant/filtermeans nor with the inner periphery of the housing. With this structure,gaps are secured between the deflecting member and the coolant/filtermeans, and between the deflecting member and the inner periphery of thehousing, whereby forming a flow-pass of the operating gas with the gaps.

In the case of arranging, in the center in the housing, the innercylindrical member with a flange portion connected to the end surface ofthe housing, desirably, an outer diameter of the flange portion in theinner cylindrical member coincides with an inner diameter of a centralopening formed in the annular portion constituting the deflectingmember. This is because a position of the deflecting member isdetermined by a combination of both elements.

In the gas generator for the air bag in which the deflecting memberincludes the tube portion having the shape capable of being arranged toface the inner periphery of the cylindrical housing and the inwardlyflange-shaped annular portion, at the upper end of the tube portion andis arranged near the coolant/filter means, a desirable arrangement issuch that the annular portion contacts with the end surface of thecoolant/filter means and the tube portion covers partly the outerperiphery of the coolant/filter means in the axial direction. With thisarrangement, the deflecting member can position and/or support thecoolant/filter means. Partly covering the outer periphery of thecoolant/filter means in the axial direction, for example, means coveringthe outer periphery of the coolant/filter means formed in thecylindrical shape partly in the axial direction, in other words, alongthe predetermined length in the axial direction. Further, can beprevented a so-called short pass such that the operating gas isdischarged without passing through the coolant/filter means, by bringingthe upper end portion of the tube portion of the deflecting member intocontact with the outer periphery of the coolant/filter means.

In the gas generator including the above deflecting member, thedeflecting member can position and/or fix the coolant/filter means. Thepositioning of the coolant/filter means can be performed, for example,by an inwardly shaping the deflecting member in flange and supportingthe outer periphery surface of the end portion of the coolant/filtermeans with a flange side (that is, an upper end side) of the tubeportion. By supporting the coolant/filter means in the above manner, thegas generator, in which the position of the coolant/filter means is notshifted even at a time of combustion of the gas generating means, can beobtained.

The housing forming an outer shell container of the gas generator can beformed by joining a diffuser shell and a closure shell. The diffusershell has a cylindrical shape with a top and a gas discharge port formedon a circumferential wall thereof. The closure shell has a cylindricalshape with a bottom and closes the diffuser shell. Both of the shellscan be formed by using various kinds of steel materials such as an ironor a stainless steel, and opening portions thereof can be joined to eachother by various kinds of bonding methods.

The coolant/filter means used in the gas generator at least cools theoperating gas generated by the combustion of the gas generating means.An example of such a coolant/filter means can be formed by winding awire mesh into a laminated layered body or by winding an expanded metalto form multi layers. Naturally, any coolant which is made of the wiremesh or the expanded metal rolled to form multi layers can be used evenif it functions for purifying the combustion product generated by thecombustion of the gas generating means.

Further, the ignition means can be a means including only an electricignition type igniter to be activated by the activating signal and alsocan be used in combination with a transfer charge to be ignited andburnt upon activation of the igniter and generate a heat gas and mistfor burning the gas generating means if required.

As the gas generating means to generate the operating gas by thecombustion, the conventionally known gas generating means can be used.Therefore, an azide gas generating means on the basis of an inorganicazide such as a conventionally and widely used sodium azide or the like,or so-called non-azide gas generating means which is not based on theinorganic azide. In this case, the gas generating means of the presentinvention can achieve a more significant effect in the case of using thegas generating means for generating the fluidized or semi-fluidizedcombustion product due to the combustion thereof, or the gas generatingmeans for generating the alkali mist due to the combustion thereof tomake the coolant/filter means eroded. This is because the deflectingmember of the present invention can adhere the combustion productcontained in the operating gas to remove by allowing the operating gasto strike against the member.

Activation of the gas generator of the present invention is performedsuch that the ignition means is activated on the activating signal, andthen the flame and the heat mist generated from the ignition meansignites and burns the gas generating means to generate the operating gasfor inflating the air bag. In general, the combustion product generateddue to the combustion of the gas generating means is contained in theoperating gas, and a part thereof can be removed while the gas ispassing through the coolant/filter means. However, in the case that thecombustion product is in a fluidized state or a semi-fluidized state,the combustion product cannot be removed by the coolant/filter meansperfectly. But the above combustion product after passing through thecoolant/filter means is accumulated in the housing after strikingagainst the deflecting member or is adhered to the deflecting member soas to be removed from the gas.

The above gas generator for the air bag of the present inventionconstitutes an air bag apparatus by including an impact sensor whichdetects an impact to operate the gas generator, an air bag whichintroduces the gas generated in the gas generator to inflate, and amodule case storing the air bag. The gas generator is stored in themodule case together with the air bag (bag body) which introduces thegenerated gas to expand, and is provided as a pad module. When the gasgenerator is provided with an electric ignition type igniter to beactivated by an electric signal, the pad module is combined with theimpact sensor detecting the impact and a control unit outputting anactivating signal to the gas generator in accordance by a signalinputted from the impact sensor, thereby forming an air bag apparatus.

In the air bag apparatus, the gas generator is activated by the impactsensor detecting the impact, and discharges a combustion gas from thegas discharge port of the housing. The combustion gas flows into the airbag, whereby the air bag breaks the module cover so as to expand out andforms a cushion for absorbing an impact between a hard structure in thevehicle and the passenger.

The gas generator for the air bag of the present invention can provide agas generator with a simple structure in which it can restrict thedischarge of the solid material generated in the housing due to thecombustion of the gas generating means and also the flame due to thecombustion of the ignition means is not directly discharged.

(2) Coolant/Filter Means Supporting Member

An object of the present invention is to provide a coolant/filter meanssupporting member, which can solve the problems of the aboveconventional coolant/filter means and provide a gas generator for an airbag in a simple structure, and to provide a gas generator for an air bagusing the same.

A constituting member used in the gas generator for the air bagaccording to the present invention is a coolant/filter means supportingmember which is arranged in the housing constituting the gas generatorand that is (1) to position at a time of disposing the coolant/filtermeans and/or at a time of activating the gas generator, and/or (2) toprevent a short pass such that the operating gas does not pass throughthe coolant/filter means, and/or (3) to prevent the heat generated dueto the combustion of the gas generating means from being transferred tothe end surface of the housing where a gas discharge port is formed,and/or (4) to securely hold and fix the coolant/filter means due to anelasticity.

That is, there is provided a coolant/filter means supporting member in agas generator for an air bag which is a constituting member used in agas generator for an air bag including, in a cylindrical housing with agas discharge port, a gas generating means to generate an operating gasfor inflating an air bag and a cylindrical coolant/filter means forcooling and/or purifying the operating gas in the housing, and thatcomprises at least an annular portion arranged oppositely to either ofend surface in the cylindrical housing and a wall portion contactingwith an inner periphery of the coolant/filter means.

A wall portion constituting the coolant/filter means supporting memberis formed to contact with the inner periphery of an end portion of thecoolant/filter means in a state of the coolant/filter means supportingmember arranged in the housing, to prevent a so-called short pass thatthe operating gas is discharged without passing through thecoolant/filter means, and to decide a position of the coolant/filtermeans.

This wall portion can be, for example, formed by bending the annularportion in the peripheral direction into a “U-shaped” cross section. Inaddition, it is possible to form by vertically connecting acylindrically formed member to the annular portion.

In the case of forming the wall portion by bending in the “U-shaped”cross section, desirably, an outside of the bent portion has a verticalsurface to the annular portion and an inside of the bent portion isinclined towards the center of the annular portion. The vertical surfacecan be securely in contact with the inner surface of the coolant/filtermeans by forming the vertical surface in the outside of the wallportion. By forming the wall portion, in a step of assembling the gasgenerator, it is possible to eliminate a possibility such that, due tovibration or the like, the position of the coolant/filter means isshifted and the gas generating means enters below the coolant/filtermeans. In other words, the coolant/filter means supporting member isarranged in a state of reversing the diffuser shell having thecylindrical shape with a top and then, the supporting means decides aposition for arranging the cylindrical coolant/filter means. At the timeof disposing the coolant/filter means, there is a risk such that the gasgenerating means charged in a hollow portion of the coolant/filter meansenters under the coolant/filter means in the case that thecoolant/filter means is shaken due to the vibration or the like inmanufacturing the gas generator. However, by forming the wall portion inthe above shape, the gas generating agent never enter between the wallportion and the coolant/filter means and, thereby such a case that thegas generating means enters under the coolant/filter means can beavoided.

It is desirable to form a bent portion bent toward the coolant/filtermeans side in a circumferential edge of an annular portion whichconstitutes a part of the coolant/filter means supporting member and isarranged oppositely to the end surface of the housing. By forming thebent portion to be brought into contact with the outer periphery of theend portion of the coolant/filter means in a state of being arranged inthe housing, a so-called short pass such that the operating gas isdischarged without passing through the coolant/filter means at a time ofactivation the gas generator can be prevented, and also thecoolant/filter means can be positioned. Desirably, the bent portion isformed so as to cover the outer periphery of the end portion of thecoolant/filter means when the annular portion of the coolant/filtermeans supporting member is disposed to contact with the end surface ofthe coolant/filter means. A length of a portion extending from the bentportion along the outer periphery of the coolant/filter means can besuitably adjusted so that the outer periphery of the coolant/filtermeans is not closed.

Further, by arranging a distance between the bent portion and the wallportion to become equal to a thickness in the radial direction of thecoolant/filter means disposed in the gas generator housing, thecoolant/filter means can be held between both portions, whereby beingable to securely position or fix the coolant/filter means.

In such case that a central opening is formed in the center of theannular portion, desirably, an inner diameter of the central opening iscontrolled so that an inner edge of the circular portion is brought intocontact with the end surface of the inner-cylindrical member arranged inthe gas-generator housing. By forming the opening in the above manner,the coolant/filter means supporting member can be positioned by theinner cylindrical member disposed in the housing and then, thecoolant/filter means supporting member can decide a position of thecoolant/filter means.

It is desirable that the annular portion of the coolant/filter meanssupporting member is formed so that, in a state of being disposed in thehousing, at least a portion which contacts with the end surface of thecoolant/filter means has an elasticity in the thickness directionthereof. An example of the annular portion can be one made of an elasticmember such as a resin or the like, or can one made by being bent into ashape or a structure capable of achieving a proper elasticity.Accordingly, even when the cylindrical coolant/filter means disposed inthe housing is not elasticated in the axial direction, the portionbecomes a buffer portion to hold the coolant/filter means between upperand lower inner surfaces of the housing due to the elasticity.

Further, desirably, the coolant/filter means supporting member is madesuch that, in a state of being disposed in the housing, at least aportion which contacts with the end surface of the coolant/filter meansis formed so as to prevent the heat from being transferred from thecoolant/filter means to the housing. For example, at least a portion onthe end surface of the coolant/filter means in the annular portion canbe made of a heat insulating member such as a resin or the like, oralternatively, bent or the like into a shape capable of securing a heatinsulating space between an inner surface of a diffuser shell and thecoolant/filter means. Accordingly, the heat of the coolant/filter meansincreased due to cooling of the operating gas can be prevented frombeing transferred to the housing, whereby avoiding a damage to the airbag.

As mentioned above, it is desirable that the coolant/filter meanssupporting member, which comprises the annular portion opposite to theend surface of the housing, the bent portion formed in the outerperiphery of the annular portion, and/or the wall portion formed in theannular portion, is formed as a single member. In this case, an examplethereof can be one formed by press-molding the stainless steel. When thecoolant/filter means supporting member is formed as a single member,effects such as to prevent a short pass of the operating gas, to avoidthe heat transmission from the coolant/filter means to the housing, tobuffer the coolant/filter means and/or to position and support thecoolant/filter means can be obtained at the same time by forming anddisposing a single member at a time of manufacturing the gas generatorfor the air bag, and thereby, the producing cost can be largely reduced.

In the coolant/filter means supporting member, when a position todispose the coolant/filter means is decided by the wall portion, thewall portion has to be formed in a length capable of supporting at leastthe end portion of the coolant/filter means.

Further, by integrally forming the cylindrical wall portion, whichcontacts with the inner periphery of the end portion of the cylindricalcoolant/filter means, with the annular portion so as to surround theinner periphery of the end portion of the cylindrical coolant/filtermeans by the wall portion, a so-called short pass such that theoperating gas passes over the coolant/filter means can be inhibited. Inthis case, it is necessary that the wall portion surrounds the innerperiphery of the end portion of the filter means entirely along theperipheral direction. Further, desirably, the wall portion is formed tocontact with the inner periphery of the coolant/filter means so that theoperating gas does not go through the portion between the wall portionand the inner periphery of the coolant to pass over the end surface ofthe coolant/filter means.

Further, the heat generated due to the combustion of the gas generatingmeans can be inhibited from being transferred to the end surface of thehousing where the gas discharge port is formed by making the annularportion of the coolant/filter means supporting member of a heatinsulating material such as ceramics or a ceramic fiber, or by formingthe annular portion into a shape and a structure capable of obtainingthe heat-insulating space. Additionally, by making the annular portionof a material which can secure an elasticity freely extendable andcompressible at least in the direction perpendicular with respect to theplane of the coolant/filter means supporting member (that is, thethickness direction of the annular portion), or by forming the annularportion in a shape and a structure capable of securing an elasticityfreely extendable and compressible in the above direction, the annularportion can securely hold and fix the coolant/filter means in thehousing due to the elasticity as an absorbing material.

Accordingly, in the above coolant/filter means supporting member, whenthe coolant/filter means supporting member of the gas generator for theair bag in which the annular portion having such a size as to cover theend surface of the coolant/filter means is integrally formed with theinner wall portion having such a size as to cover the inner periphery ofthe end portion of the coolant/filter means, it is possible to (1)position the coolant/filter means and (2) prevent a so-called short passsuch that the operating gas passes over the coolant/filter means. Inthis case, desirably, the wall portion is formed to cover the innersurface of the end portion of the coolant/filter means entirely alongthe peripheral direction and the circumferential wall is formed in sucha size as to contact with the inner periphery of the end portion of thecoolant/filter means.

Further, in the coolant/filter means supporting member, by making atleast the annular portion, which covers the end surface of thecoolant/filter means, of a heat insulating material, or by forming theannular portion in a shape capable of securing the space, (3) it ispossible to prevent the heat generated due to the combustion of the gasgenerating means from being transferred to the end surface of thehousing where the gas discharge port is formed. And in the case offorming the annular portion so as to be elasticated in the directionvertical with respect to the plane thereof such as making the annularportion of a member having a proper elasticity or forming the annularportion in a structure having an elasticity, (4) the coolant/filtermeans can be securely held and fixed due to the elasticity.

The coolant/filter means supporting member is preferably used in apyrotechnic gas generator particularly using the coolant/filter means,and there can be realized a gas generator for an air bag achieving aproper effect at a time of manufacture and activation.

That is, there is provided a gas generator for an air bag comprising, ina cylindrical housing with a gas discharge port, an ignition means toactivate a gas generator, a gas generating means to generate anoperating gas for inflating an air bag upon activation of the ignitionmeans, a cylindrical coolant/filter means to purify and/or cool theoperating gas, wherein a coolant/filter means supporting member formedas a single member is disposed near the cylindrical coolant/filtermeans. Such a coolant/filter means supporting member prevents theoperating gas from passing between an end surface of the coolant/filtermeans and an inner periphery of the housing, and/or positions thecoolant/filter means, and/or prevents the heat from being transferredfrom the coolant/filter means to the housing, and/or supports thecoolant/filter means between the upper and lower inner surfaces of thehousing due to an elasticity

The above gas generator can be realized, for example, by arranging anyone of coolant/filter means supporting members mentioned above near thecylindrical coolant/filter means disposed in the housing. In this case,desirably, that the coolant/filter means supporting member is arrangedso as to bring the annular portion thereof into contact with the endsurface of the coolant/filter means and to partly cover the innerperiphery of the coolant/filter means in the axial direction. Thecoolant/filter means is positioned and/or supported by thecoolant/filter means supporting means, and it is desirable that the gasgenerator is structured so that the position is not shifted even by thecombustion pressure of the gas generating means.

The housing forming an outer shell container of the gas generator can beformed by joining a diffuser shell, which is formed in a cylindricalshape with a top and has a gas discharge port formed in acircumferential wall thereof, to a closure shell which closing thediffuser shell and has a cylindrical shape with a bottom. Both shellscan be formed by using various kinds of steel materials such as an iron,a stainless steel or the like, and opening portions thereof can bejoined to each other by various kinds of joining methods.

The coolant/filter means includes a structure achieving a function ofremoving the combustion product contained in the operating gas and acooling function of the operating gas, in addition to the coolant/filtermeans made of a wire mesh used conventionally for cooling the operatinggas generated due to the combustion of the gas generating means. Also, acoolant/filter, which is formed into a complex gap structure by using alaminated wire mesh body so as to cool the operating gas as well as tocollect the combustion product in the operating gas, can be employed.Still, in the case that the coolant/filter means supporting member ofthe present invention is formed to have an elasticity in the thicknessdirection thereof, since this can function as an absorbing member, evena coolant/filter means, which is made of a plain-stitch wire mesh or anexpanded metal and hardly elasticated in the axial direction, can beemployed. The coolant/filter means is generally formed in asubstantially cylindrical shape, and is arranged outside the portionwhere the gas generating means is stored. It is possible to provide anouter layer made of a laminated wire mesh body, a porous cylindricalbody, an annular belt body or the like on an outer periphery of thecoolant/filter means for the purpose of supporting and restricting thecoolant/filter means from expanding due to the combustion of the gasgenerating means.

In the gas generator in accordance with the present invention, as thegas generating means stored in the housing in order to generate theoperating gas by the combustion, a non-azide gas generating agent or thelike which is not based on the inorganic azide in addition to the azidegas generating agent on the basis of the conventionally used inorganicazide, for example, the sodium azide, can be used and these are notlimited to the specific gas generating means.

Further, the ignition means is used for igniting and burning the abovegas generating means when activated upon the activating signal, and canbe used in a structure being constituted only by the electric ignitiontype igniter to be activated on the activating signal, or in combinationwith the transfer charge to be ignited and burnt upon activation of theigniter, and to generate the heat gas and mist for burning the gasgenerating means, if required.

The gas generator for the air bag is accommodated in the module casetogether with the air bag (bag body) to introduce the gas generated inthe gas generator so as to inflate, thereby forming the air bagapparatus. In the air bag apparatus, the gas generator is activated whenreacting upon the impact sensor detecting the impact and the operatinggas is discharged from the gas discharge port of the housing. Theoperating gas flows into the air bag, and then, the air bag breaks themodule cover so as to inflate, thereby forming a cushion absorbing theimpact between the hard structure in the vehicle and the passenger.

In accordance with the coolant/filter means supporting member of the gasgenerator for the air bag in the present invention, with a simplerstructure, the short pass of the operating gas at the end surface of thefilter means can be prevented so as to purify and/or cool all of theoperating gas by the coolant/filter means, and the cooled cleanoperating gas can be discharged to the air bag. Also, increase of atemperature in the housing caused by the activation of the gas generatorcan be made less, particularly in the end surface of the housing wherethe gas discharge port is formed, and thereby a damage to the air bagdue to the contact with the housing can be avoided.

Further, at a time of manufacturing the gas generator, thecoolant/filter means supporting member can position the coolant/filtermeans, and therefore, the space for accommodating the gas generatingmeans formed inside of the coolant/filter means can be secured at afixed position. Further, since the coolant/filter means supportingmember is formed so as to have an elasticity at least in a thicknessdirection thereof, it can also function as the absorbing means betweenthe inner surface of the housing and the end surface of thecoolant/filter means, thereby being able to securely fix the coolantmeans in the housing.

(3) Housing Having Structure to Prevent Short Pass

An object of the present invention is to provide a housing of a gasgenerator for an air bag in a simple structure which can securelysupport and fix the coolant means and can prevent a short pass of theoperating gas, and a gas generator using the same.

The gas generator for the air bag in accordance with the presentinvention is characterized by a structure of the housing, andparticularly characterized by a combined structure for arranging andfixing the coolant means.

That is, in the present invention, there is provided a gas generator foran air bag comprising, in a cylindrical housing with a gas dischargeport, a gas generating means to generate an operating gas for inflatingan air bag, and a cylindrical coolant means to cool and/or purify theoperating gas in the housing, in which an outer peripheral edge of anend portion of the coolant means is adhered and/or supported a bentportion or a step portion formed on an inner surface of an upper endportion and/or an inner surface of a lower end portion of thecylindrical housing at a time of assembling the gas generator and/or ata time of activating the gas generator.

Desirably, the bent portion or the step portion formed on the innersurface of the upper end portion and/or the inner surface of the lowerend portion of the cylindrical housing is formed so as to adhere and/orsupport the outer peripheral edge of either or both end portions of thecoolant means at a time of assembling the gas generator and/oractivating the gas generator, and thereby preventing the operating gasfrom passing between the end surface of the coolant means and the innersurface of the housing contacting therewith (a so-called short pass). Inthe present specification, the upper portion of the housing correspondsto a ceiling surface of the gas-generator housing, and the lower endportion corresponds to a bottom surface of the gas-generator housing.Further, the time when the gas generator is activated includes at leasta time when the operating gas generated due to the combustion of the gasgenerating means passes through the coolant means.

Accordingly, in the present invention, the outer peripheral edge of theend portion in the coolant means may be adhered to and/or supported bythe bent portion or the step portion formed on the inner surface of theupper end portion and/or the inner surface of the lower end portion ofthe cylindrical housing before the gas generator is activated, or afterthe gas generator is activated (for example, at a time when theoperating gas passes through the coolant means).

The outer peripheral edge of the end portion of the coolant means can beadhered to and supported by the inner surface of the bent portionbetween the end portion and the circumferential wall portion of thecylindrical housing. In this case, it is possible to prevent theoperating gas from passing between the end surface of the coolant meansand the inner surface of the housing contacting therewith by adheringthe outer peripheral edge of the end portion in the coolant means to theinner surface of the bent portion of the cylindrical housing. In thiscase, desirably in the housing, the inner surface of the circumferentialwall portion in the upper end side and/or the lower end side is formedto be inclined from the end portion, spreading outwardly and radially.When it is formed in this manner, a gap functioning as a flow-path ofthe operating gas in the outside of the coolant means can be secured,and the entire surface of the coolant means can be utilized by thefunction of the gap. For example, when the housing is formed by adiffuser shell having a cylindrical shape with a top with the gasdischarge port and a closure shell having a cylindrical shape with abottom closing an open end of the diffuser shell, the inner surface ofthe circumferential wall portion at least in one shell can be formed tobe inclined from the end portion, spreading outwardly and radially. Inother words, at a time of forming the closure shell, the inner surfaceof the circumferential wall portion thereof can be formed in a shapespreading outwardly and radially, from the bottom surface towards theopen end. As the shape mentioned above, in addition to an inverseconical trapezoidal shape, there can be employed a shape obtained byinclining from a peripheral edge of the bottom surface to spread andmaking the end portion rise up. However, in view of making a productionof the housing easy, it is desirable to form the inner surface of thecircumferential wall portion in an inverted conical trapezoidal shape soas to make the bent portion less.

Therefore, in accordance with the present invention, there is provided agas generator for an air bag characterized in the housing having theabove shape, in other words, the housing for the gas generator, in whichthe inner surfaces of the circumferential wall portions in the upper endside and/or the lower end side thereof are inclined to spread outwardlyand radially from the end surface.

The bent portion can be formed between the circumferential wall portionof the housing and the upper end portion and/or the lower end portion ofthe housing so as to adhere the outer peripheral edge of the cylindricalcoolant means onto the inner surface of the bent portion. Accordingly,the coolant means can be positioned at a time of assembling the gasgenerator, the coolant means can be fixed after assembling the gasgenerator, and then, the short pass of the operating gas can beeffectively prevented at the coolant means end surface at a time ofactivating the gas generator. In this case, it is desirable that in thehousing, an interior angle between the inner surface of thecircumferential wall portion and the inner surface of the upper endportion and/or the inner surface of the lower end portion is to be 90 to150 degrees and more preferably of 90 to 135 degrees. This is because abest gap width can be secured, in view of a size and a capacity of awhole of the gas generator, by adjusting the angle to be in the aboverange. In other words, desirably, the housing of the gas generator is ascompact and light as possible, and, by adjusting the angle between theinner surface of the circumferential wall portion and the inner surfaceof the upper end portion and/or the inner surface of the lower endportion to be the above range, downsizing the housing of the generatorcan be obtained and also the gap forming the gas flow path can beformed.

The above housing can be formed by casting, forging, press-molding thediffuser shell having the gas discharge port and the closure shellforming the accommodating space to join the shells. Joining the shellscan be performed with various kinds of welding methods, such as anelectron beam welding, a laser beam welding, a TIG welding, a projectionwelding. In the case of forming the diffuser shell and the closure shellby press-molding various kinds of steel plates such as a stainless steelplate, manufacturing both shells becomes facilitated and a manufacturingcost can be reduced. Further, by forming the bent portion in both shellsas little as possible, the press-molding can be easily performed. Withrespect to the material of the diffuser shell and the closure shell, astainless steel plate is desirable, however, a material such as a nickelplated steel plate can be used.

In the above gas generator, in addition to a conventional coolant meansmade of the metal wire mesh and used for cooling the operating gasgenerated due to the combustion of the gas generating means, a coolantmeans such as to have functions for removing the combustion productcontained in the operating gas and cooling the operating gas can beused. Further, it is possible to employ the coolant/filter formed in acomplex gap structure by using the laminated wire mesh body to cool theoperating gas and collect combustion residues in the operating gas. Inthe present invention, in view of supporting and fixing the coolantmeans by the bent portion formed in the end portion of thecircumferential wall of the housing, the coolant means can employ such astructure as not to be deformed due to passage of the operating gas. Inthis case, the coolant means can be formed such that at least a tensilestrength in the radial direction is between 2450 and 19600 N (between250 and 2000 kgf), more preferably between 4900 and 14700 N (between 500and 1500 kgf), or the like so as to have a strength enough to stop thecoolant means from expanding outwardly and radially when the operatinggas is cooled and/or purified. The above coolant means can be, forexample, formed by using a plain stitch wire mesh or an expanded metal.Still, the outer periphery of the coolant means can be provided with anouter layer composed of the laminated wire mesh body, the porouscylindrical body, the annular belt body or the like to support thecoolant, for the purpose of suppressing expansion due to the combustionof the gas generator.

Further, in the present invention, the coolant means which expandsoutwardly and radially at a time of cooling and/or purifying theoperating gas can be used. In such a coolant means, desirably, thecoolant means is formed so that the outer peripheral edge of the endportion of the coolant means which expands outwardly and radially isadhered to and/or supported by the bent portion or the step portionformed in the inner surface of the upper end portion and/or the innersurface of the lower end portion in the cylindrical housing. With thisstructure, when the operating gas passes through the coolant means, itis possible to prevent the operating gas from passing between the endsurface of the coolant means and the inner surface of the housingcontacting therewith (so-called short pass).

Accordingly, the coolant means used in the present invention is requiredto be structured such that, after the gas generator is activated, theouter peripheral edge of the end portion is adhered to and/or supportedby the bent portion or the step portion in the housing, or adheredand/or supported further more, however, before activating the gasgenerator, it is not an essential requirement to adhere and/or supportthe bent portion or the step portion in the housing to the outerperipheral edge of the end portion of the coolant means.

As the gas generating means which burns to generate the operating gas,in addition to the azide gas generating agent on the basis of theconventionally and wildly used inorganic azide, for example, a sodiumazide, the non-azide gas generating agent or the like which is not basedon the inorganic azide can be used, and these are not limited to thespecific gas generating means.

Further, the ignition means is used for igniting and burning the abovegas generating means when activated upon the activating signal, and canbe used in a structure being constituted only by the electric ignitiontype igniter to be activated on the activating signal, or in combinationwith the transfer charge to be ignited and burnt upon activation of theigniter, and to generate the heat gas and mist for burning the gasgenerating means, if required.

And, in the above housing, it is possible to arrange a short passpreventing means surrounding the inner periphery of the end portion ofthe coolant means, an absorbing and/or heat insulating member arrangedbetween the coolant means end surface and the inner surface of thehousing, a deflecting member arranged in a gap secured between the outerperiphery of the coolant means and the inner wall surface of the housingto shield the gas discharge port, or the like, if required.

Further, in the present invention, there can be provided a housing of agas generator for an air bag which is preferably used in the pyrotechnictype gas generator mentioned above.

That is, there is provided a cylindrical housing of a gas generator foran air bag to generate the operating gas for inflating the air bag uponthe impact, wherein a bent portion or a step portion adhering to and/orsupporting an outer peripheral edge of either or both end portions ofcoolant means disposed in the housing at a time of assembling the gasgenerator and/or at a time of activating the gas generator is formed onan inner surface of an upper end portion and/or an inner surface of alower end portion in the cylindrical housing.

In terms of putting the housing into practice, the housing can be easilyutilized according to the description of the gas generator for the airbag mentioned above.

Further, the above gas generator for the air bag is accommodated in themodule case together with the air bag (bag body) to introduce the gasgenerated in the gas generator so as to inflate, thereby forming the airbag apparatus. In the air bag apparatus, the gas generator is activatedwhen reacting upon the impact sensor detecting the impact and theoperating gas is discharged from the gas discharge port of the housing.The operating gas flows into the air bag, and then, the air bag breaksthe module cover so as to inflate, thereby forming a cushion absorbingthe impact between the hard structure in the vehicle and the passenger.

In accordance with the present invention, while having a simplestructure, the coolant means can be securely fixed even when the coolantmeans is exposed to the pressure generated by the operating gas passingthrough, and at a time of manufacturing the gas generator, the coolantmeans can be kept in a fixed position, and further, the housing for theair bag gas generator, in which a so-called short pass such that theoperating gas is discharged from the gas generator without passingthrough the coolant means is effectively inhibited, can be realized.

Since the housing has a simple structure, manufacturing thereof can beproceed easily and also the manufacturing cost can be reduced.

(4) Coolant Composed of Laminated Wire mesh

An object of the present invention is to provide a coolant/filter of agas generator for an air bag which solves a problem in the conventionalart mentioned above, being easy to be manufactured with a lowermanufacturing cost as well as securing a satisfying safety in activationof the gas generator, and a gas generator using the same.

The coolant/filter in accordance with the present invention is mainlyused for the purpose of cooling the operating gas for inflating the airbag in the gas generator for the air bag, and is formed by winding aplain stitch wire mesh being comparatively easily produced andinexpensive so as to form a cylindrical shape. By forming the coolant inthis manner, the coolant/filter of the gas generator for the air bagwhich is manufactured easily with a lower manufacturing cost can berealized. This coolant/filter is structured such as to perform at leasteither of purifying and cooling the operating gas, and is the coolantand/or the filter used in the gas generator for the air bag.

Namely, the gas generator for the air bag in the present inventionincludes a coolant/filter disposed in the housing of the gas generatorfor the air bag in order to cool and/or purify the operating gas forinflating the air bag, in which the coolant/filter is formed in acylindrical shape obtained by laminating the wire mesh, and has thepressure loss in the range of 9.8 to 980 Pa, preferably 98 to 980 Pa or9.8 and 98 Pa at the flow rate of 1000 litter/minute at 20° C. Thepressure loss is selected in view of effects and functions in the caseof the coolant/filter applied to the gas generator. That is, if thepressure loss is smaller than 9.8 Pa, it is impossible to sufficientlyachieve the function of cooling and purifying the operating gasgenerated due to the combustion of the gas generating means (the coolingand purifying function of the coolant/filter) when being used in the gasgenerator, and if the pressure loss is larger than 980 Pa, passage ofthe operating gas is disturbed when being used in the gas generator, anda pressure in the gas generator (that is, in the housing) becomes toohigh.

In accordance with the present invention, in view of effects orfunctions or the like of the above coolant/filter, the pressure loss isadjusted as described above in order to solve the above problems.

The pressure loss of the coolant/filter can be measured by flowing apredetermined amount of air from the inside of the coolant/filter. Thatis, in the opening portions of the cylindrically formed coolant/filter,a first supporting plate provided with an air-feeding pipe is attachedto one end portion thereof and a second supporting plate closing so asto prevent the air from being leaked is attached to the other endportion thereof. Further, a second manometer is attached to the secondsupporting plate. Therefore, it is designed such that the air whichenters inside from the pipe attached to the first supporting plate fixedto one end portion of the cylindrical coolant/filter is all flowedoutside from the cylindrical side surface portion of the coolant/filter.In this case, it is necessary that the pipe feeding the predeterminedamount of air has a sufficiently large cross-sectional area and a flatsmooth inner surface in order to accurately measure the pressure loss.The pipe is provided with a first flow rate meter for feeding apredetermined amount of air into the coolant/filter. At this time, aseal means such as a packing is applied to a surface where thesupporting plate and the end portion of the coolant/filter contact witheach other, so as to strongly grip the coolant/filter by the supportingplate and prevent the air from leaking through the contacted surface.When supplying a predetermined amount of air in this state, a part ofthe air, which enters the inside of the cylindrical coolant/filter,flows out through the side surface portion thereof and a pressure isdecreased. This can define a ventilating resistance of thecoolant/filter. That is, a value, which is indicated by the secondpressure manometer attached to the second supporting plate in one endportion, is a value of pressure loss in the coolant/filter.

This coolant/filter can be made of the plain stitch wire mesh, and forexample, can be formed in a cylindrical shape. The plain stitch wiremesh corresponds to a structure obtained by combining metal wirematerials (hereinafter, also referred to a “strand”), which extend intwo directions, to cross each other, and there can be providedstructures having various kinds of wire diameters and gap densities.

In particular, in the case of forming with the plain stitch wire mesh,since the plain stitch wire mesh is structured such as to have variouskinds of wire diameters and gap densities, the wire diameter and thebulk density can be easily selected, and the pressure loss can be easilyadjusted by laminating the mesh. Consequently, manufacturing and amanufacturing cost can be preferable.

Desirably, the coolant/filter in the present has a bulk density of 0.1to 3.5 g/cm³, preferably 1.0 to 3.5 g/cm³, or 1.5 to 3.0 g/cm³, or 2.0to 3.0 g/cm³. For example, the bulk density can be set in the rangelarger than 2.4 g/cm³ but smaller than 3.5 g/cm³, or smaller than 3.0g/cm³.

Further, it is desirable that the coolant/filter in the presentinvention is made of a wire mesh composed of a metal wire materialhaving a wire diameter of 0.1 to 1.0 mm and, particularly it isdesirable to be made of a wire mesh composed of a metal wire materialhaving a wire diameter of 0.2 to 0.6 mm. If the coolant/filter of thepresent invention is made of the metal wire material having the wirediameter mentioned above, the coolant/filter can be hardly damaged bythe heat of the operating gas when being applied to the gas generator,and can function satisfactory for cooling and purifying the operatinggas. In particular, on account of avoiding a damage by heat of theoperating gas, the metal wire material having a wire diameter largerthan 0.3 mm and further the metal wire material having a wire diameterlarger than 0.6 mm can be used. However, even in this case, it isnecessary to include the pressure loss and the bulk density mentionedabove, or a number of meshes per 1 inch square or the like.

Further, desirably, a tensile strength in the radial direction is setbetween 2450 and 19600 N (between 250 and 2000 kgf), and particularlydesirably, the tensile strength is set between 4900 and 14700 N (between500 and 1500 kgf). If the present coolant/filter is provided with such atensile strength, the deformation thereof can be inhibited and thecoolant can effectively cool and purify the operating gas when beingapplied to the gas generator and purifying the operating gas forinflating the air bag.

Further, at a time of manufacturing the coolant/filter, it is desirableto form that a compression margin in the axial direction in the case ofapplying force of 4900 N (500 kgf) in the axial direction is to be inthe range of 0.1 to 10% of the axial length before compression, and itis particularly desirable to form so as to be in the range of 1 to 5%.In this case, the “compression margin” is a distance to be compressed inthe axial direction thereof when the force of 4900 N (500 kgf) in theaxial direction of the coolant/filter is applied, and thereby a rigidityin the axial direction can be confirmed.

Further, desirably the coolant/filter in the present invention is madeof a wire mesh in which a number of meshes per 1 inch square (645.16mm²) is between 12 and 32, and particularly desirably, the number of themeshes is between 16 and 24. By using such a wire mesh, collecting andcooling effects of the combustion product can be obtained, and at thesame time, a damage by heat can be avoided. In other words, if thenumber of the meshes per 1 inch square is increased, the collecting andcooling effects of the combustion product can be improved, however, thecoolant can be easily damaged by heat, and if the number of the meshesis reduced, the inverse actions are obtained, neither of which ispreferable.

Still, in the present invention, the “bulk density” and the “tensilestrength” can be measured with a standard method.

Further, in the case of forming the coolant/filter in the presentinvention with the plain stitch wire mesh, it is desirable to form sothat either of strands which cross each other to two directions becomesparallel to the axial direction of the cylindrical coolant/filter. Byadjusting the direction of one strand in the above manner, thecoolant/filter can increase a strength against the axial direction.Further, by forming the other strand so as to be along the peripheraldirection of the cylindrical coolant/filter, a strength of thecoolant/filter against the direction (that is, the radial direction) towhich the coolant is deformed by the operating gas can be improved.Further, by forming the coolant in such a manner, the case such that thestrands are unraveled from each other at a time of producing can beeliminated. That is, unless the strands are woven in a directionvertical or parallel to the axial direction of the coolant/filter to bemanufactured, the strands are unraveled, and a performance isdeteriorated.

The present coolant/filter can be formed in the manner described below.

That is, the plain stitch wire mesh made of various kinds of steelmaterial such as a stainless steel or the like is wound into acylindrical body, and at least the end thereof is welded. The plainstitch wire mesh can be composed of a metal wire material, for example,having a wire diameter of 0.1 to 1.0 mm (desirably 0.2 to 0.6 mm), andcan be wounded in the perpendicular direction to the extending directionof either of wire materials which cross each other. With respect to thewinding number of the wire mesh, it is desirable to adjust so as to havea bulk density of 0.1 to 3.5 g/cm³ (desirably 1.0 to 3.5 g/cm³, or 1.5to 3.0 g/cm³, or 2.0 to 3.0 g/cm³) and have a pressure loss of 9.8 to980 Pa at 1000 litter/minute and 20° C. (desirably 9.8 to 98 Pa, or 98to 980 Pa). Having the tensile strength in the radial direction is inthe range of 2450 to 19600 N (desirably of 4900 to 14700 N), it isdesirable to have a compression margin of 0.1 to 10% (desirably 1 to0.5%) thereof, compressing in the axial direction by force of 4900 N.

With respect to winding the plain stitch wire mesh into the cylindricalbody, a plain stitch wire mesh in a strip shape can be wound so as toform a multi-layer, and additionally, plain stitch wire meshes wound ina cylindrical shape can be combined so as to form a multi-layer.

As the stainless steel of the wire mesh material, such as SUS304,SUS310S, SUS316 (in JIS standard codes) can be used. SUS304(18Cr-8Ni-0.06C) exhibits an excellent corrosion resistance as anaustenite stainless steel.

A reinforcing ring body having a plurality of through holes in an entireperiphery thereof can be fitted to both or either of the outside and theinside of the present coolant/filter, however, this is not necessarilyrequired. Further, the present coolant/filter can be formed to have adouble structure by being combined with a cylindrically formed wire meshbody having a different wire diameter, a bulk density, a pressure loss,a compression margin and/or a tensile strength if required.

Any one of elements constituting the above present invention has asatisfying characteristic, and can exhibit advantageous effects in thecoolant/filter of the gas generator for the air bag. Namely, the presentinvention also provides the coolant/filter of the gas generator for theair bag with a structure described as follows. In this case, thefollowing features (41) to (48) can be optionally combined.

(41) A coolant/filter used in a gas generator for an air bagcharacterized in that the coolant/filter is formed in a cylindricalshape obtained by laminating a wire mesh, and has a pressure loss of 9.8to 980 Pa (desirably 9.8 to 98 Pa, or 98 to 980 Pa) at a flow rate of1000 litter/minute at 20° C.

(42) A coolant/filter used in a gas generator for an air bagcharacterized in that the coolant/filter is a bulk density of 0.1 to 3.5g/cm³ (desirably 1.0 to 3.5 g/cm³, or 1.5 to 3.0 g/cm³, or 2.0 to 3.0g/cm³).

(43) A coolant/filter used in a gas generator for an air bagcharacterized in that the coolant/filter is formed by using a metal wirematerial with a wire diameter of 0.1 to 1.0 mm.

(44) A coolant/filter used in a gas generator for an air bagcharacterized in that the coolant/filter is formed so that a compressionmargin in the case of applying a force of 4900 N in the axial directionthereof is 0.1 to 10% of an axial length before compressing thecoolant/filter.

(45) A coolant/filter used in a gas generator for an air bagcharacterized in that the coolant/filter is formed to have a tensilestrength in the radial direction is between 2450 and 19600 N.

(46) A coolant/filter used in a gas generator for an air bagcharacterized in that the coolant/filter is formed in a cylindricalshape by using a wire mesh, and is formed so that either of wirematerials, which cross each other to constitute the wire mesh, is alongthe axial direction of the coolant/filter.

(47) A coolant/filter used in a gas generator for an air bagcharacterized in that the coolant/filter is formed by using a wire meshsuch that a number of meshes per 1 inch square (645.16 mm³) is between12 and 32.

(48) A coolant/filter used in a gas generator for an air bagcharacterized in that the coolant/filter is made of a wire mesh, and thewire mesh is a plain stitch wire mesh formed by plain-weaving a metalwire material.

Further, in the gas generator for the air bag, the gas generator for theair bag of the present invention can be obtained by using thecoolant/filter for cooling the operating gas.

That is, there is provided a gas generator for an air bag comprising, ina housing with a gas discharge port, a gas generating means to generatean operating gas for inflating an air bag and a coolant/filter to coolthe operating gas, in which the coolant/filter in accordance with thepresent invention is used as the coolant/filter.

In this gas generator, preferably, a gas generating means for togenerate a mist in a molten state as a by-product produced due to thecombustion is employed. An example thereof may be a gas generating agentcontaining a fuel and an oxidant and employing a basic copper nitrate asthe oxidant. As the fuel, a guanidine derivative or a mixture thereofcan be used.

In the case that the gas generating means which generates the mist inthe molten state as the by-product due to the combustion is used,preferably, in a the housing, a deflecting plate is provided in a flowpath of the operating gas which passes through the coolant/filter to thegas discharge port. By arranging the deflecting plate in the abovemanner, the mist in the molten state contained in the operating gasafter passing through the coolant/filter strikes against and/or adheredto the deflecting plate, thereby being removed from the operating gas.

Accordingly, desirably, the deflecting member provided with the annulardeflecting plate for deflecting the flow of the operating gas isincluded in the housing. And also desirably, the deflecting member isdisposed so that the deflecting plate may cover the outside of thecoolant/filter but at a distance, and the deflecting plate is formed tohave a size covering at least the part projected horizontally from gasdischarge port. In the case that a gap functions as the flow path of theoperating gas is formed between the inner wall surface of the housingand the outer periphery of the coolant/filter, desirably, the deflectingplate exists in the gap, and the housing and the coolant/filter arearranged at a distance at least over the parts thereof projectedhorizontally from a gas discharge port.

The gas generator for the air bag is stored in the module case togetherwith the air bag (bag body) to inflate due to introducing the gasgenerated in the gas generator, thereby forming an air bag apparatus.The air bag apparatus discharges the operating gas from the gasdischarge port of the housing when the gas generator is activated,reacting upon an impact sensor detecting the impact. The operating gasflows into the air bag, and accordingly, the air bag breaks the modulecover so as to inflate, and forms a cushion absorbing the impact betweenthe hard structure in the vehicle and the passenger.

Since the coolant/filter of the present invention uses the plain stitchwire mesh which is comparatively easily produced and inexpensive, thecoolant/filter of which manufacturing cost is restricted can berealized. Further, at manufacture of the coolant/filter, thecoolant/filter is formed simply by winding the wire mesh, therebyfacilitating a manufacture of the coolant/filter itself.

Further, in the gas generator using the coolant/filter, it is possibleto realize a gas generator for the air bag which can restrict a wholecapacity and weight, and securely remove the solid mist generated due tothe combustion of the gas generating means by the combination with thedeflecting plate. Further, such a coolant/filter can hardly deformedeven by passage of the operating gas, and accordingly, a so-called shortpass of the operating gas at the end surface of the coolant/filter canbe effectively inhibited.

(5) Housing Having Bent Portion in Inlet Port of Igniter

In accordance with the present invention, there is provided a housingfor a gas generator preferably used in manufacturing the gas generatorwith a restricted overall height, in which the problems mentioned aboveis solved and the igniter included in the ignition means is securelyfixed, and a gas generator with a restricted overall height.

The housing of the gas generator for the air bag in accordance with thepresent invention is characterized by a shape and a structure of aportion for arranging and fixing an igniter or a member for fixing theigniter.

That is, the housing of the gas generator for the air bag according tothe present invention is a cylindrical housing used in a gas generatorfor an air bag which generates an operating gas for inflating the airbag upon the impact, characterized in that the cylindrical housing has,in either end surface thereof, an opening portion for inserting andfixing an igniter or an igniter supporting member arranged in thehousing, the opening portion is provided with a connecting portion forfixing the inserted igniter or igniter supporting member, and theconnecting portion is provided in inner side of the housing rather thanon the end surface having the opening portion. The opening portionprovided in either end surface of the cylindrical housing can be formedso as to be provided with a tubular portion bent inside the housing.

Accordingly, even at the same height of the housing, it is possible toincrease an internal capacity thereof, and an end of the tubular portionbent inside the housing supports an under plate which is arranged in thehousing to support the gas generating means so as to block movement ofthe under plate in the direction of stress (that is, in the oppositeside supporting the gas generating agent).

The opening portion formed in a bottom surface of the cylindricalhousing is provided with the connecting portion for fixing the igniteror the igniter supporting member inserted to the opening portion. Theigniter or the igniter supporting member can be fixed, for example, by awelding or the like. Further, the igniter can be provided in thevicinity thereto with a transfer charge to be ignited and burnt upon anactivation of the igniter for generating a heat gas and mist to burn thegas generating means, whereby forming the ignition means. The igniter isformed by being provided with a metal portion for arranging and fixingin the housing, and this metal portion can be integrally formed with aportion to be activated upon the activating signal by a resin materialor the like, or alternatively, both portions can be integrally formed bycrimping the metal portion. In the case of directly accommodating theigniter in the opening portion, it is possible to integrally fix themetal portion to the connecting portion of the opening portion with awelding or the like. Further, in the case that the igniter supportingmember for arranging the igniter in the housing is provided, it ispossible to integrally fix the igniter supporting member in which theigniter is fixed to the connecting portion of the opening portion with awelding or the like. For example, in the case of the gas generator inwhich the inner cylindrical member is arranged in the housing and theignition means accommodating chamber is defined in the inside thereof,the igniter can be fixed to the lower end opening of the innercylindrical member by crimping. In this case, the inner cylindricalmember functions as the igniter supporting member. Accordingly, in sucha state, the inner cylindrical member can be integrally fixed to theconnecting portion of the opening portion by a welding or the like. Ifthe igniter supporting member or the igniter is integrally fixed to theconnecting portion of the opening portion by a welding or the like,these portions can be prevented from dropping. At this time, byproviding the connecting portion of the opening portion for fixing theigniter supporting member or the igniter inside the housing rather thanon the end surface having the opening portion of the housing, it ispossible to restrict the overall height of the housing.

In the present invention, the housing is realized by the substantiallycylindrical housing, in which the connecting portion for fixing theignition supporting member or the ignition is provided inside ratherthan on the end surface of the housing, that is, in the center in theaxial direction of the housing. In this case, a rib in a concavo-convexshape could be formed on the end surface of the housing in order tosecure the strength, and, at this time, the connecting portion may beprovided inside the housing rather than the most protruding portion inthe housing.

Further, in accordance with the present invention, there can be alsoprovided a cylindrical housing used in a gas generator for an air bag togenerate an operating gas for inflating an air bag upon the impact,characterized in that an opening portion provided with a tubular portionbent inside the housing is formed on either end surface of thecylindrical housing.

In this housing, the opening portion is formed on either end surface,and the opening portion is provided with the tubular portion bent insidethe housing.

In the present invention mentioned above, the opening formed in the endportion of the housing is formed so that the igniter or the ignitersupporting member arranged in the housing is stored, and the tubularportion formed in the opening is formed so as to be in inner contactwith the outer periphery of the igniter or the inner tube member.Further, it is desirable that the tubular portion, with which theopening portion on either end surface of the housing is provided, isformed in the range of 10 to 100% of the axial length of the housing.Further, desirably, the tubular portion is formed to have the axiallength of 4 to 37 mm. This is because, by forming the tubular portion tohave the above length, the igniter supporting member or the igniterstored in the opening portion is inhibited from being shaky, and can besupported more securely. Further, in the case of setting the length ofthe tubular portion to 100% of the axial length of the housing, sincethe tubular portion itself can function as the inner cylindrical member,it is possible to form a so-called double cylinder type gas generator inwhich the interior of housing is partitioned into two chambers only bytwo members, that is, the diffuser shell and the closure shell.

Further, desirably in the above housing, the periphery of the openingportion is inclined inside the housing towards the center of the openingportion at the end surface having the opening portion. This is because,by forming in the above manner, even in the case of welding the ignitersupporting member or the igniter near the inlet port of the openingportion, the welded portion can be provided inside rather than the endsurface of the housing, that is, in the center in the axial direction ofthe housing. Further, in view of structure, by forming the periphery ofthe opening portion to be inclined, it is possible to prevent the stressfrom being concentrated in this portion.

The above housing above can be formed by a diffuser shell with the gasdischarge port having the cylindrical shape with the top, and theclosure shell having the cylindrical shape with the bottom and formingthe inner space of the housing together with the diffuser shell, and inthis case, the opening can be formed in the closure shell side.

Each of the shells can be formed by a casting or a forging as well as apress-molding of various kinds of metal materials such as the stainlesssteel. The shells formed by various kinds of methods can form the innerspace for accommodating the gas generating means or the like by beingintegrally joined in such a state as to face each other oppositely. Bothshells can be joined by various kinds of welding methods, for example,an electron beam welding, a laser beam welding, a TIG welding, aprojection welding or the like. In the case that the diffuser shell andthe closure shell are formed by press-molding various kinds of steelplates such as a stainless steel plate or the like, both of the shellscan be easily manufactured, and the manufacturing cost can be reduced.With respect to the material of the diffuser shell and the closureshell, a stainless steel is particularly desirable, however, a materialsuch as a nickel plated steel plate may be employed.

Further, the present invention also provides a gas generator for an airbag characterized by being formed with the housing.

That is, there is provided a gas generator for an air bag comprising, ina cylindrical housing with a gas discharge port, an ignition means whichincludes an igniter to be activated upon the activating signal, a gasgenerating means to generate an operating gas for inflating the air bag,in which the housing according to the present invention is used as thecylindrical housing.

The ignition means is activated upon the activating signal or the like,used for igniting and burning the gas generating means, and constitutedonly by an electric ignition type igniter to be activated upon theactivating signal, and further can be used in combination with atransfer charge to be ignited and burnt upon the activation of theigniter for generating a heat gas and a mist to burn the gas generatingmeans, if required. In the gas generator in which the inner cylindricalmember is arranged in the housing and the ignition means accommodatingchamber is defined in the inner cylindrical member, the ignition meansincluding the igniter is stored and fixed in the inner cylindricalmember, and the inner cylindrical member is stored and fixed in theopening portion formed in either end of the housing. That is, in thiscase, the inner cylindrical member functions as the igniter supportingmember. Further, it is possible to directly fix the igniter includingthe metal portion to the opening portion, and in this case, the metalportion is integrally fixed to the connecting portion of the openingportion by a welding or the like.

In this gas generator, it is necessary to use a housing for the gasgenerator having at least the above features of the present invention,however, it is possible to suitably adjust the other structure than thehousing, for example, a composition and a shape of the gas generatingmeans, existence of the coolant, the filter or the like for coolingand/or purifying the operating gas generated due to the combustion ofthe gas generating means, or the like, in correspondence to theactivating performance. For example, with respect to the gas generatingmeans to burn for generating the operating gas, in addition to an azidegas generating agent based on the conventionally and widely usedinorganic azide such as a sodium azide, a non-azide gas generating agentor the like not based on the inorganic azide can be used. Further, withrespect to the housing itself, the structure other than the portions inthe vicinity of the opening portion in either end of the above, such asa size and a number of the gas discharge port, a size of the housing, awhole shape, can be suitably adjusted in correspondence to the operatingperformance, the accommodating space or the like.

The gas generator for the air bag mentioned above is stored in a modulecase together with an air bag (bag body) to inflate by introducing thegas generated in the gas generator, thereby forming an air bagapparatus. In the air bag apparatus, the gas generator is activated whenreacting upon the impact sensor detecting the impact and an operatinggas is discharged from a gas discharge port. The operating gas flowsinto the air bag, whereby the air bag breaks the module cover so as toinflate, and forms a cushion absorbing the impact between a hardstructure in the vehicle and the passenger.

In accordance with the present invention, it is possible to provide ahousing which is preferably used in manufacturing the gas generatorwhich has a simple structure and a restricted overall height, and cansecurely fix the igniter included in the ignition means, and the gasgenerator with a restricted overall height.

In particular, in the case that the opening portion formed on either endsurface of the cylindrical housing and storing the igniter or the likeis provided with the tubular portion bent inside the housing, an end ofthe tubular portion is useful for supporting the under plate supportinga gas generating means in the combustion chamber.

Further, although the housing of the present invention can restrict theoverall height, it is possible to further increase the internal capacityin the housing, in the gas generator having the same outer diameter andheight.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view showing a gas generator for an air bagusing a deflecting member or the like in embodiment according to theaspects (1) and (4) of the present invention.

FIG. 2 is a perspective view showing a deflecting member in otherembodiment according to the aspect (1) of the present invention.

FIG. 3 is a perspective vertical cross sectional view showing oneembodiment of a coolant/filter means supporting member according to theaspect (2) of the present invention.

FIG. 4 is a vertical cross sectional view showing a gas generator for anair bag formed by using the coolant/filter means supporting memberaccording to the aspect (2).

FIG. 5 is a vertical cross sectional view showing a gas generator for anair bag formed by using the coolant/filter means supporting memberaccording to other aspect of the aspect (2).

FIG. 6 is a perspective view showing one embodiment of a coolant/filteraccording to the aspect (4) of the present invention.

FIG. 7 is a perspective vertical cross sectional view showing a gasgenerator according to the aspects (1), (3) and (5) of the presentinvention.

FIG. 8 is a schematic view of an air bag apparatus including any one ofthe aspects (1) to (5) of the present invention.

DESCRIPTION OF CODES

 1 or 101 Diffuser Shell  2 or 102 Closure Shell  3 or 103 Housing  4Inner Cylindrical Member  5 or 107 Coolant/Filter  6 or 104 Igniter  7or 105 Transfer Charge  8 or 106 Gas Generating Agent  11 Gas DischargePort  12 Supporting Portion  13 Ventilating Portion  16 Annular Portion 17 Wall Portion  18 Deflecting Member  19 Tube Portion  19 InnerCylindrical Member  21 Expanded Portion  23 Central Opening  50(Diffuser Shell Side) Circular Portion  51 (Diffuser Shell Side)Inclining Portion  52 (Diffuser Shell Side) Circumferential Wall Portion 54 (Closure Shell Side) Circular Portion  55 (Closure Shell Side)Circumferential Wall Portion  56 (Closure Shell Side) Bent Portion  57(Diffuser Shell Side) Bent Portion 150 Coolant/Filter Means SupportingMember 151 Annular Portion 152 Wall Portion 154 Bent Portion 321Stainless Steel Strand 321a, 321b Strand 200 Gas Generator 201 ImpactSensor 201 Semiconductor Type Acceleration Sensor 203 Module Case 204Air Bag 207 Steering Wheel

PREFERRED EMBODIMENTS FOR THE INVENTION

The respective embodiments of the present invention will be describedwith reference to the drawings.

A gas generator for an air bag provided with the capabilities mentionedabove of the present invention can be realized in the followingembodiments.

Embodiment 1—(1) Deflecting Member

FIG. 1 is a vertical cross sectional view showing one embodiment of agas generator for an air bag in accordance with the present invention.The gas generator shown in this drawing comprises a housing 3 which isformed with a diffuser shell 1 in a cylindrical shape with a top havinga gas discharge port 11 and a closure shell 2 in a cylindrical shapewith a bottom closing the diffuser shell 1, and that includes anignition means constituted of an electric type igniter 6 and a transfercharge 7 and a gas generating means (which is, a gas generating agent 8)to generate an operating gas for inflating the air bag on the actuationof the ignition means, and further, coolant/filter means (which is, acoolant 5) to cool the operating gas generated by the combustion of thegas generating agent 8 is disposed between a combustion chamber 9storing the gas generating agent 8 and the housing 3. And, a deflectingmember 18 having a tube portion 19 is arranged in the end portion of thediffuser shell 1 side of the coolant 5.

The ignition means is stored in an ignition means accommodating chamber10 which is secured in a inner cylindrical member 4 having a flangeportion 24 welded to the inner surface of an upper portion inside thehousing 3, and a space where the ignition means is stored can becommunicated with the combustion chamber 9 provided in the outside ofthe cylindrical member via a plurality of flame transferring ports 14formed in a circumferential wall of the inner cylindrical member 4.

In this embodiment, the gas generating agent 8, which generates afluidized or semi-fluidized combustion product due to the combustion,can be used as the gas generating means stored in the combustion chamber9. Even such a gas generating agent 8 can be used because the combustionproduct generated due to the combustion can be unfailingly removed byusing a deflecting member 18 described below. An example of the gasgenerating agent 8 can be a gas generating agent 8 containing a fuel andan oxidant in which the basic copper nitrate is used as the oxidant.

Further, as the coolant 5 disposed on the outside in the radialdirection of the combustion chamber 9, a wire mesh coolant 5 formed intoa cylindrical shape can be used in the present invention even if thewire mesh coolant has a little elasticity in the axial direction. Thisis because, by disposing the deflecting member described below, theassembly thereof can be realized. Such a coolant 5 can produced bywinding an expanded metal or a plain-stitch wire mesh into a cylindricalshape.

In the present embodiment, the deflecting member 18 comprises a tubeportion 19 partly covering an outer periphery of the coolant 5 in theaxial direction, an annular portion 16 bent inwardly into a flange shapeon the upper end portion of the tube portion 19 to contact with an endsurface of the coolant 5, and a wall portion 17 integrally formed withthe annular portion 16 to contact with an inner periphery of the coolant5. Among these, the tube portion 19 is formed so as to have a shape anda length covering a gas discharge port 11 in the circumferential wall ofthe housing 3 from the inside of the housing 3.

The tube portion 19 is formed in a substantially cylindrical shape whichcovers from the end surface, on the diffuser shell side, of the coolant5 to a portion where the gas discharge port 11 is formed, furtherextending downwards (i.e. to the closure shell 2 side). An expandedportion 21 expanding outwardly and radially is formed on the tubeportion 19, and, because of this expanding portion, the tube portion isdisposed without having most thereof contacted with the inner peripheryof the housing 3 and the coolant 5. Accordingly, the operating gas,after passing through the coolant 5, strikes against the inner surfaceof the tube portion 19 in the deflecting member 18, and passes betweenthe outer periphery of the tube portion 19 and the inner periphery ofthe housing 3 to be discharged from the gas discharge port 11. Further,this tube portion 19 prevents a flame discharged from such as theflame-transferring port 14 of the inner cylindrical member 19 includingthe ignition means inside from passing through the coolant 5 to bedischarged from the gas discharge port 11 directly. Accordingly, thedeflecting member 18 in this embodiment is formed so that the tubeportion 19 extends more downwardly than the portions where the gasdischarge port 11 and the flame transferring port 14 are provided.

In this case, when the tube portion 19 is too long, there is a risk suchthat the tube portion 19 is expanded out or deformed by a pressure ofthe operating gas generated due to the combustion of the gas generatingmeans to close the gas discharge port 11. Therefore, in the presentembodiment, even in the tube portion 19 with a sufficient length, inorder to prevent the tube portion 19 from being expanded out by thepressure of the operating gas, a supporting portion 12 bent in a flangeshape outwardly and radially is formed on the end portion of the openingside (which is the opening portion in the closure shell 2 side). Thesupporting portion 12 can stop the tube portion 19 expanding by thepressure of the operating gas since an end thereof contacts with theinner periphery of the housing 3.

In the present embodiment, as shown in a plan view of the deflector inaccordance with another embodiment shown in FIG. 2, ventilating portions13 notched at a predetermined interval along the peripheral directioninwardly in the radial direction are formed in the supporting portion12. With these portions, the operating gas, after passing through thecoolant 5, can reach the gas discharge port 11 through the ventilatingportion 13. As described above, in the case of forming the supportingportion 12 at the end of the tube portion 19 in the deflecting member18, the end of the supporting portion 12 contacts with the inner wallsurface of the housing 3, however, at least a circumferential wall alongthe axis of the tube portion 19 is disposed so as not to be in contactwith the inner periphery of the housing 3 and the coolant 5, whereby aflow path of the operating gas can be secured.

Further, the deflecting member 18 shown in the present embodimentcomprises the inwardly flange-shaped annular portion 16, integrallyformed with the tube portion 19, and the wall portion 17 covering aninner periphery of an upper portion (in the diffuser shell 1 side) ofthe coolant 5 is formed with the annular portion 16. Accordingly, theend portion in the diffuser shell side of the coolant 5 has the innerperiphery—the end surface—the outer periphery thereof integrallysurrounded, whereby it is possible to prevent a short pass of theoperating gas between the end surface of the coolant 5 and the innerperiphery of the housing 3.

Further, the tube portion 19 is bent in a crank shape to form anexpanded portion 21 expanding outwardly and radially in the closureshell 2 side (the lower end side) the portion in the diffuser shell 1side (that is, the annular portion 16 side) is formed to correspond tothe outer diameter of the coolant 5. With this portion formed in thismanner, the coolant 5 is interposed and positioned between the portioncorresponding to the outer diameter of the coolant 5 in the tube portion19 and the wall portion 17 of the annular portion 16. The coolant 5 heldby the deflecting member 18 in this manner does not move due to passageof the actuating gas and securely A position of the coolant 5 gripped bythe deflecting member 18 is kept at the predetermined position.

Further, in the annular portion 16, the portion contacting with the endsurface of the coolant 5, that is, a portion interposed between the endsurface of the coolant 5 and the inner surface of the housing 3 is abuffer portion between the coolant 5 and the inner surface of thehousing. That is, the portion is formed as a structure being freelyelasticated in the axial direction of the coolant 5. By forming theportion in this manner, it becomes the buffer portion at a time ofproviding the coolant 5 means, and the coolant 5 can be held between theupper and lower inner surfaces of the housing 3 due to the elasticity.In accordance with the present embodiment, an elasticity is secured bybending the portion corresponding to the end surface of the coolant 5 soas to be inclined outwardly, however, any shapes capable of achieving anelasticity can be employed, and further, an elastic member can be formedby using such as a resin. Additionally in the present invention, asshown in FIG. 7, in the annular portion 16, the portion contacting withthe end surface of the coolant 5 can be formed in a plate shape. In thegas generator shown in FIG. 7, the deflecting member shown in FIG. 2 isused.

Further, it is desirable that, in the annular portion 16 of thedeflecting member 18, the portion corresponding to the end surface ofthe coolant 5 is formed to achieve a suitable heat insulating effect,which prevents the heat of the coolant 5 increased due to the cooling ofthe operating gas from being transferred to the diffuser shell 1 andfurther securely avoids a damage to the air bag. Such a heat insulatingeffect can be achieved, for example, by bending the portion outwardly asshown in the drawing (FIG. 1) so as to secure an heat-insulating spacebetween the coolant 5 and the housing 3.

The annular portion 16 shown in the present embodiment has an endsurface of its central opening 23 contacted with the flange portion 24of the inner cylindrical member 4 provided in the housing 3 as shown inFIG. 1. Accordingly, a position of the deflecting member 18 isdetermined in the housing 3, and then a position of the coolant 5 isdetermined by the deflecting member 18. That is, the gas generator canbe easily manufactured by coinciding an outer diameter of the flangeportion of the inner cylindrical member 4 disposed in the housing 3 withan inner diameter of the central opening formed in the annular portion16 constituting the deflecting member 18.

In the gas generator formed in the above manner, the transfer charge 7is ignited and burnt by the igniter 6 actuated by an actuating signal,and the flame thereof is discharged into an accommodating space of thegas generating agent 8 after passing through the flame-transferring port14 of the inner cylindrical member 4. The flame of the transfer charge 7ignites and burns the gas generating agent 8. And even in the case thata part of the flame directly passes through the coolant 5, it strikesagainst the tube portion 19 of the deflecting member 18, therebypreventing the flame from being discharged directly through the gasdischarge port 11. The operating gas generated from the gas generatingagent 8 ignited by the flame of the transfer charge 7 passes through thecoolant 5 and reaches a gap 20 secured between the outer periphery ofthe coolant 5 and the inner periphery of the housing 3. There is a casethat in the operating gas produced from some kinds of the gas generatingagents may include the combustion product in a fluidized state or asemi-fluidized state after passing through the coolant 5, but thecombustion product strikes on and adheres to the tube portion 19 of thedeflecting member 18 provided in the gap 20 to be removed from theoperating gas. Further, a material generated due to such an erosion ofthe coolant 5 adheres to the tube portion 19 of the deflecting member 18to be removed from the operating gas.

Accordingly, the combustion product or the like in the operating gas canbe securely removed, and the operating gas discharged from the gasdischarge port 11 is made clean.

In FIG. 1, the gas discharge port 11 and the flame-transferring port 14are respectively closed by a seal tape 15, and the gas generating agent8 is supported by the under-plate and stored in the combustion chamber.Further, the member described as the deflecting member 18 in the presentembodiment can also function as a mist collecting member or aflame-preventing plate by the same structure.

Embodiment 2—(2) Coolant/Filter Means Supporting Member

FIG. 3 is a perspective vertical cross sectional view in a used stateshowing one embodiment of a coolant/filter means supporting member of agas generator for an air bag in accordance with the present invention.

A coolant/filter means supporting member (a coolant means supportingmember 150) shown in this drawing is structured such that an annularportion 151 arranged oppositely to aside where a gas discharge port 111is formed, that is, an inner surface of an end portion of a diffusershell 101, a bent portion 154 formed in the outer peripheral edge of theannular portion and a wall portion 152 which contacts with an innerperiphery of an end portion of coolant/filter means (a coolant 107) at atime of being disposed are integrally formed in the housing of the gasgenerator by using various kinds of steel materials such as a stainlesssteel. This wall portion 152 is integrally formed by bending the annularportion 151 so as to have a size capable of covering a whole surface ofthe inner periphery of the end portion of the coolant 107 in theperipheral direction with the predetermined width. Further, a distancebetween the bent portion 154 and the wall portion 152 is set to athickness of the coolant 107.

The wall portion 152 constituting a part of the coolant means supportingmember 150 can function as positioning at a time of arranging thecoolant 107 by making the outer periphery thereof contact with the innerperiphery of the coolant 107, and can also prevent a so-called shortpass such that the operating gas generated due to the combustion of thegas generating agent passes over the end surface of the coolant 107.Further, the bent portion 154 formed in the peripheral edge of theannular portion 151 also contacts with the outer peripheral edge of theend portion of the coolant 107 to function as positioning at a time ofarranging the coolant 107 and prevent the short pass of the operatinggas.

Further, the annular portion 151 constituting a part of the coolantmeans supporting member 150 and arranged oppositely to an end surface inwhich the gas discharge port is formed (that is, a ceiling inner surfaceof the diffuser shell 101) is formed so that a portion opposite to anend surface 128 of the coolant 107 is inclined downwards in the radialdirection to the outer periphery. Accordingly, the coolant meanssupporting member 150 can exhibit an elasticity capable of freely beingelasticated in the direction perpendicular to the plane. Further, byforming the annular portion 151 in the above manner, a space 153 isformed between the end surface 128 of the coolant 107 and an innersurface 129 of the upper portion of the housing. The space portion 153can function as a heat insulating space 153 preventing the heat of thecoolant 107 accumulated when the operating gas passes from beingtransferred to the end surface of the diffuser shell 101 on which thegas discharge port is formed. In this case, substantially the sameeffect can be expected even when the annular portion is made of a membersuch as one having a suitable elasticity and a heat insulating capacitybut formed so as not to be inclined downwards in the radial direction tothe outer periphery.

Embodiment 3—(2) Coolant/Filter Means Supporting Member

FIG. 4 is a cross sectional view showing a gas generator for an air bagincluding a coolant means supporting member 150 (that is, acoolant/filter means supporting member) shown in Embodiment 2 mentionedabove.

The gas generator shown in this drawing is constructed by defining ahousing 103 comprising a diffuser shell 101 and a closure shell 102 intotwo chambers of an ignition means accommodating chamber 123 and a gasgenerating agent combustion chamber 122 by an inner cylindrical member113. The ignition means accommodating chamber 123 includes an igniter104 and a transfer charge 105 as ignition means to be activated upon theimpact for igniting and burning a gas generating agent 106, and thecombustion chamber 122 includes the gas generating agent 106 to beignited and burnt by the ignition means for generating the operating gasand a substantially disk-shaped under plate 118 for supporting the gasgenerating agent 106 as well as blocking a movement thereof. A pluralityof gas discharge ports 111 are arranged at equal intervals in theperipheral direction in a circumferential wall portion 110 of thediffuser shell 101, and the gas discharge port 111 is closed by a sealtap 125. The inner cylindrical member 113 is arranged to be fitted in acentral hole 112 of the closure shell 102. The diffuser shell 101 andthe closure shell 102 form the housing 103 by overlapping respectiveflange portions 115 and 116 near a position on the central horizontalcross section in the axial direction of the housing 103 and joining bothshells by a laser beam welding.

The coolant 107 (the coolant/filter means), which is disposed in thehousing 101 in order to purify and cool the gas generated by theignition and combustion of the gas generating agent 106, is arranged tosurround the gas generating agent 106, and defines an annular chamber,that is, a combustion chamber 122 for the gas generating agent, in theperiphery of the inner-cylindrical member 113. The coolant 107 can beformed by laminating stainless steel plain stitch wire mesh in theradial direction and compressing them in the radial direction and theaxial direction. As the coolant 107, even a coolant which is hardlyelasticated in the axial direction can be used. In particular, in thecoolant 107 shown in FIG. 3, the coolant is formed shorter in the axialdirection at a degree of the coolant means supporting member 150arranged on the end surface 128 in the diffuser shell 101 side. A gap109 is formed between the outer circumferential wall of the housing 103and the coolant 107, and the gap 109 functions as a gas flow path.

The annular portion 151 of the coolant means supporting member 150described in the Embodiment 2 mentioned above is arranged to beinterposed between the axial end portion of the coolant 107 and theupper inner surface 129 of the diffuser shell 101. In the annularportion 151 arranged oppositely to the inner periphery of the housing, aportion where the end surface of the coolant contacts is formed toincline downwards in the radial direction to the outer periphery. Andthe annular portion 151 is formed integrally with the cylindrical wallportion 152 which covers the inner periphery of the upper portion of thecoolant 107 (that is, the diffuser shell side). The annular portion 151is held between the coolant 107 and the diffuser shell 101, whereby thespace portion 153 is formed therebetween. The space portion 153functions as a heat insulating space for preventing the heat from beingtransferred from the coolant to the diffuser shell. At the same time,the annular portion 151 is freely elasticated in the directionperpendicular to the plane, and it is possible to held the coolant 107between the upper and lower end surfaces of the housing due with thiselasticity. With respect to the annular portion, as in a gas generatorfor an air bag of another embodiment shown in FIG. 5, the annularportion can be arranged on the end surface of the coolant 107 withoutbeing inclined.

Further, since the coolant means supporting member 150 is provided witha wall portion 152 and a bent portion 154, the operating gas generateddue to the combustion of the gas generating agent 106 does not pass overthe end surface of the coolant 107. Accordingly, all of the operatinggas passes through the coolant 107, and the suitably cooled operatinggas in which the combustion product generated by the combustion isremoved is discharged from the gas discharge port.

In this embodiment, the wall portion 152 is made by bending the annularportion 151 to be substantially “U-shaped”. More particularly, the wallportion 152 is formed so that an outer side thereof (that is, a sidewhere the coolant 107 contacts) has a surface vertical to the annularportion, and an inner side of the bent portion (that is, in theinner-cylindrical member 113 side) is inclined so as to be recessedtoward the center of the annular portion. By forming the wall portion152, it is possible to prevent the gas generating agent 106 stored inthe combustion chamber 122 from entering into the end surface of thecoolant 107 at a time of assembling the gas generator.

Further, an opening portion (that is, a central opening 155) having asize capable of contacting with a flange-shaped end surface of theinner-cylindrical member 113 is formed at the center of the annularportion 151. Accordingly, when the inner-cylindrical member 113 is fixedto the diffuser shell 101, the coolant means supporting member 150 isdisposed, being positioned by the central opening 155, and the coolant107 can be fixed, being positioned by the coolant means supportingmember 150. Therefore, the gas generator can be assembled in morefacilitated and secure manner.

Also, a substantially porous cylindrical perforated basket (not shown)can be disposed on the inner periphery of the coolant 107 to protect thecoolant 107 from the flame due to the combustion of the gas generatingagent 106 and prevent a direct contact between the gas generating agent106 and the coolant 107.

The substantially disk-shaped under plate 118 arranged in the combustionchamber 122 of the gas generating agent defined in the outside of theinner-cylindrical member 113 in the housing 101 has a circular portion119 contacting with the gas generating agent 106 and a central hole 120in which the outer circumferential wall of the inner-cylindrical member113 is fitted. The circular portion 119 supports the gas generatingagent 106 and blocks the movement thereof to eliminate a risk such thatthe gas generating agent 106 is crushed due to a vibration and a surfacearea thereof is changed. A crimped portion 121 is formed in the endportion in the igniter 104-accommodated side in the inner-cylindricalmember 113, and the igniter 104 is fixed by the crimped portion 121.Further, a plurality of flame-transferring ports 126 arranged at equalintervals are provided on the circumferential wall of theinner-cylindrical member 113, and the flame transferring ports 126 areclosed by a seal tape 127.

In the gas generator shown in this drawing, the transfer charge 105 isignited and burnt by the igniter 104 activated upon the impact, and theflame thereof breaks the seal tape 127 closing the flame-transferringport 126 of the inner-cylindrical member 113 and flows into thecombustion chamber 122. The gas generating agent 106 in the combustionchamber 122 is ignited and burnt by the flame of the transfer charge 105so as to generate the operating gas. The operating gas is purified andcooled while passing through the coolant 107, then passes through thegap 109, and finally breaks the seal tap 125 closing the gas dischargeport 111 to be discharged from the gas discharge port 111.

In this gas generator, at a time of manufacturing, the coolant 107 canbe positioned by the wall portion 152 and the bent portion 154 of thecoolant means supporting member 150, and the coolant 107 can be securelyfixed with the elasticity of the annular portion 151. Further, at a timeof activation, since the short pass of the operating gas is restrictedby the wall portion 152 and the bent portion 154 of the coolant meanssupporting member, all of the operating gas can be purified and/orcooled by the coolant 107. Further, since the annular portion 151 of thecoolant means supporting member 150 prevents the heat accumulated in thecoolant 107 from being transferred to the diffuser shell, the diffusershell 101 does not gain a high temperature at activation of the gasgenerator, whereby eliminating a risk such as a damage to the air bagmore reliably.

Embodiment 4—(3) Housing Which Prevents a Short Pass

FIG. 7 is a cross sectional view showing a gas generator for an air bagwhich comprises the housing for the gas generator in accordance with oneembodiment of the present invention.

The gas generator shown in this drawing comprises, in a housing 3 with agas discharge port 11, a ignition means including an electric typeigniter 6 and the transfer charge 7, and the gas generating means (thatis, the gas generating agent 8) to generate the operating gas forinflating the air bag upon activation of the ignition means, andfurther, a coolant/filter means (that is, the coolant 5) to cool theoperating gas generated due to the combustion of the gas generatingagent 8 is disposed between the combustion chamber 9 in which the gasgenerating agent 8 is stored and the circumferential wall portion of thehousing 3. Further, the deflecting member 18 having the tube portion 19is arranged in the end portion of the coolant 5 in the diffuser shell 1side.

The ignition means is stored in the ignition means accommodating chamber10, and this ignition means accommodating chamber 10 is obtained insidethe inner cylindrical member 4 provided with the flange portion 24welded to the inner surface of the upper end portion in the housing 3.The ignition means accommodating chamber 10 can communicate with thecombustion chamber 9 provided in the outside of the cylindrical membervia a plurality of flame-transferring ports 14 formed in thecircumferential wall of the inner cylindrical member 4.

In this embodiment, the housing 3 comprises the diffuser shell 1 formedin substantially the cylindrical shape with the top having the gasdischarge port, and the closure shell 2 formed in substantially thecylindrical shape with the bottom closing the diffuser shell. Bothshells can be obtained by press-molding a stainless steel.

In the present embodiment, the diffuser shell 1 has a first circularportion 50 forming a ceiling surface (that is, an upper end portion) ofthe housing, an inclining portion 51 inclined downwards to surround thecircular portion 50, a circumferential wall portion 52 descendingperpendicularly to the circular portion from the inclining portion andprovided with a plurality of gas discharge ports 11 along the peripheraldirection, and a flange portion 53 extending in the radial directionfrom the circumferential wall portion. And on the other hand, theclosure shell 2 has a second circular portion 54 which forms a bottomsurface (that is, a lower end portion) of the housing and is providedwith an ignition means receiving hole in the center, a circumferentialwall portion 55 which is bent from a peripheral edge of the secondcircular portion 54 and inclines as to spread outwardly and radially,and a flange portion 58 spreading outwardly and radially from a end ofthe circumferential wall portion. Both shells formed in this manner areintegrally formed by joining to each other.

In this housing 3, the circumferential wall portion 55 of the closureshell 2 is inclined towards the circumferential wall portion 52 which iswider outwardly and radially than the first circular portion 50 becauseof the inclining portion 51 of the diffuser shell 1, and the bentportion 56 formed between the second circular portion 54 of the closureshell 2 and the circumferential wall portion 55 is adjusted so that aninterior angle θ thereof becomes between 90 and 135 degrees.

Further, in the present embodiment, the first and second circularportions 50 and 54 are formed in the same size. Accordingly, the outerperiphery of the upper end of the coolant 5 disposed in the housing issupported by the bent portion 57 formed between the first circularportion 50 and the inclining portion 51 in the diffuser shell 1,interposing the deflecting member 18, and the outer periphery of thelower end surface of the coolant 5 is directly supported by the bentportion 56 formed between the second circular portion 54 and thecircumferential wall portion 55 in the closure shell 2. As mentionedabove, by supporting the outer peripheries of the upper and lower end ofthe coolant 5 by the bent portions 56 and 57 formed in the housing, at atime of disposing the coolant 5, the coolant is positioned and supportedby the bent portions. Further, at a time of activating the gasgenerator, the coolant 5 is pressed to contact with, and is supported bythe bent portions, whereby the movement thereof is blocked, and theupper end portion of the coolant 5 is surrounded by the deflectingmember 18 so as to be adhered to the bent portion 57 of the diffusershell 1, and the outer peripheral edge of the lower end of the coolant 5is directly adhered to the bent portion 56 of the closure shell 2,thereby preventing the operating gas from passing between the innersurface of the housing and the coolant 5 (that is, the short pass).

In this case, with respect to forming the housing, a rib-likereinforcing member and/or a reinforcing step portion is formed in bothor either of the first circular portion 50 of the diffuser shall and thesecond circular portion 54 of the closures shell so as to improve astrength of the housing.

The coolant 5 disposed in the housing preferably employs a structurewhich does not expand outwardly and radially by a pressure generated dueto passage of the operating gas. This is because, if the coolant 5 isexpanded due to passage of the gas, the gap 20 secured between thecoolant 5 and the inner periphery of the housing is closed and does notactually function as a gas-flow path. Accordingly, the coolant 5 in thepresent embodiment is formed so that a tensile strength in the radialdirection becomes 12054 N (1230 kgf).

The deflecting member 18 is useful in the case that the gas generatingagent 8 generates the combustion product in a fluidized state or asemi-fluidized state due to the combustion. In other words, thedeflecting member 18 can remove the combustion product generated due tothe combustion of the gas generating agent by adhering the combustionproduct to the tube portion 19 thereof or by allowing the product tostrike thereagainst to dorp. Further, in the deflecting member 18, sincea annular portion 16 which contacts with the end surface of the coolant5 is formed to have a suitable elasticity, even a wire mesh coolant 5being a little elasticated in the axial direction can be used as thecoolant 5 disposed in the outside of the combustion chamber 9 in theradial direction. Further, in the deflecting member 18, the wall portion17 which contacts with the inner periphery of the coolant 5 isintegrally formed with the annular portion 16. By this structure, thecoolant 5 can be positioned and fixed, and a so-called short pass thatthe operating gas is discharged without passing through the coolant canbe inhibited.

In the gas generator formed in the above manner, a transfer charge 7 isignited and burnt by an igniter 6 activated by receiving the activatingsignal, and a flame thereof is discharged to the accommodating space forthe gas generating agent 8 through the flame-transferring port 14 of theinner cylindrical member 4. The flame of the transfer charge 7 ignitesand burns the gas generating agent 8, and even though a part thereofdirectly passes through the coolant 5, the flame strikes against thetube portion 19 of the deflecting member 18, thereby preventing theflame from being directly discharged through the gas discharge port 11.The operating gas generated from the gas generating agent 8 ignited bythe flame of the transfer charge 7 passes through the coolant 5 to reachthe inside of the gap 20 secured between the outer periphery of thecoolant 5 and the inner periphery of the housing 3. In the case that thecombustion product in a fluidized state or a semi-fluidized state iscontained in the operating gas after passing through the coolant 5, thecombustion product is removed from the gas by being allowed to strikeagainst and adhere to the tube portion 19 of the deflecting member 18disposed in the gap 20.

In FIG. 7, the gas discharge port 11 and the flame-transferring port 14are respectively closed by the seal tape 15, and the gas generatingagent 8 is supported by the under plate 22 and stored in the combustionchamber. Further, in the present embodiment, the member described as thedeflecting member 18 can also function as a mist collecting member or aflame preventing plate in the same structure.

Embodiment 5—(4) Coolant Composed of Laminated Wire Mesh“Coolant/Filter”

The coolant/filter 5 of the gas generator for the air bag in accordancewith the present invention is formed, as shown in FIG. 6, by winding aplain stitch wire mesh made of a stainless steel strand 321 having awire diameter of about 0.4 mm so as to form a cylindrical shape, andthen laminating twelve layers in the peripheral direction. In thepresent embodiment, there is used the wire mesh in which a number ofmeshes per 1 inch square (645.16 mm²) is 20. The coolant/filter 5 shownin this drawing is formed so that the strands 321 a and 321 bplain-stitched in two directions cross rectangularly to each other, thestrand 321 a extending to one direction is wound to the same directionas the axial direction of the cylindrically formed coolant/filter, andthe other strand 321 b is wound along the peripheral direction of thecoolant/filter 5. Namely, in the present embodiment, there is used theplain stitch wire mesh obtained by combining the strands 321 a and 321 bso as to be crossed rectangularly to each other. In this embodiment, forexample, the plain stitch wire mesh in which the wire diameter is 0.4 mmand the number of the meshes per 1 inch square is 20 is used, and in thecase of compressing in the axial direction by the force of 4900 N, acompression margin in the axial direction becomes not more than about 5%of the margin before the compression. That is, the cylindricalcoolant/filter is formed so that the axial length is about 31 mm and thecompression margin is in the range of 1 to 1.5 mm. Further, thecoolant/filter is formed so that the tensile strength in the radialdirection is 12054 N (1230 kgf), the bulk density is 2.66 g/cm³, and thepressure loss is in the range of 294 to 441 Pa (30 to 45 mmH₂O) at theflow rate of 1000 litter/minute at 20° C.

When the coolant/filter 5 is formed in this manner, manufacturing can beproceed easily and the manufacturing cost can be reduced. In otherwords, by using the plain stitch wire mesh which is comparatively easilyproduced and inexpensive, the manufacturing cost can be reduced, and thecoolant/filter is manufactured simply by winding, and manufacturethereof can be facilitated.

Further, like the coolant/filter 5 shown in this embodiment, byarranging one strand 321 a of the crossed strands 321 along the axialdirection of the coolant/filter 5, the respective strands 321 a and 321b can support and restrict it from expansion and compression in theaxial and the radial direction. Consequently, when the coolant/filter 5is disposed in the housing to purify the operating gas, thecoolant/filter 5 does not expand radially and can be hardly deformed,thereby restricting the short pass of the operating gas between the endsurface of the coolant/filter 5 and the inner surface of the housing.That is, when the operating gas passes, an accidental bending of thecoolant/filter 5 can be avoided, and it is possible to prevent theoperating gas from passing between the end surface of the coolant/filter5 and the inner surface of the housing.

Embodiment 6—(4) Coolant Composed of Laminated Wire Mesh “Gas Generatorfor Air Bag”

FIG. 1 shows an embodiment in which one embodiment of the coolant/filter5 of the present invention is applied to the gas generator for the airbag. The gas generator includes the housing 3 comprising the diffusershell 1 formed in a substantially cylindrical shape with a top and theclosure shell 2 formed in a substantially cylindrical shape with abottom, the central cylindrical member 4 disposed at the center portionin the housing 3, and the present coolant/filter 5 provided so as tosurround the central cylindrical member 4.

The diffuser shell 1 is formed by press-molding the stainless steelplate, and a plurality of gas discharge ports 11 are arranged on thecircumferential wall thereof in the peripheral direction at equalintervals. The closure shell 2 is formed by press-molding the stainlesssteel plate and has an opening hole in the center thereof, a hole edgethereof is bent outwardly in the axial direction so as to form the bentportion 12, and an inner periphery of the bent portion forms the centralhole 13.

The central cylindrical member 4 is made of the stainless steel tube,one end thereof is stored inside the central hole 13, and a flangeoutwardly formed in the other end is welded to the inner surface of thediffuser shell 1. The central cylindrical member 4 also forms theignition means accommodating chamber 10 for accommodating the ignitionmeans inside the same, and has one row of through holes 14 in the otherend side of the circumferential wall. The ignition means comprises theigniter 6 to be activated on a signal outputted from a sensor (notshown) and the transfer charge 7 to be ignited by the igniter 6, and theigniter 6 is disposed in the ignition means accommodating chamber 10 andis fixed by crimping one end of the central cylindrical member 4. Therow of through holes 14 is closed by the aluminum tape 15.

There is used the coolant/filter 5 which is formed by winding the plainstitch wire mesh so as to form a multiple layers, and the coolant/filter5 is disposed to surround the central cylindrical member 4. Thecoolant/filter 5 also defines an annular chamber, that is, a combustionchamber 9 in the periphery of the central cylindrical member 4, that is,between the periphery of the central cylindrical member 4 and the innersurface of the coolant/filter 5.

The gas generating agent 8 formed in a cylindrical shape with singlehole is charged as the gas generating means in the combustion chamber 9,and is supported by an annular under plate 22. In the presentembodiment, as the gas generating agent 8, an agent containing a fueland an oxidant is used, and as the oxidant, the basic copper nitrate isused. When using the above gas generating agent 8, the copper mist inthe molten state is generated due to the basic copper nitrate, however,since a melting point of the copper is high (1053° C.), the mist can beeasily removed by cooling to about 1000° C., and therefore the dischargeof the mist out of the gas generator can be restricted.

The coolant/filter 5 is positioned by an annular member 18 and themovement thereof is restricted. The annular member 18 is formed bypress-molding the stainless steel plate, and includes the annularportion 16 partly covering the inner surface of the diffuser shell 1 anda wall portion 17 cylindrically bent from the annular portion 16 so asto contact with the inner surface of the end portion of thecoolant/filter 5, to surround the outward flange of the centralcylindrical member 4. It is desirable that the portion contacting withthe end surface of the coolant/filter 5 in the annular portion 16 isformed to have a suitable elasticity. In other words, it is desirable tobe formed in a shape capable of being elasticated at least in the axialdirection of the coolant/filter 5, such as using the elastic member orhaving a substantially “S-shaped” cross section. This is performed forthe purpose of eliminating a disadvantage at a time of arranging in thehousing 3 caused by the fact that the coolant/filter 5 shown in thisembodiment is structured such that one of the strands extending in twodirections is formed to be along the axial direction of thecoolant/filter 5 and no axial elasticity exists. Further, since the wallportion 17 is formed in the annular member 18 so as to support the innersurface of the end portion of the coolant/filter 5, it is possible toprevent a so-called short pass such that the operating gas generated bythe combustion of the gas generating agent 8 passes over the end surfaceof the coolant/filter 5.

Further, in this embodiment, since the gas generating agent 8 employsthe basic copper nitrate as the oxidant, the copper mist in the moltenstate is generated due to the combustion thereof. Then, in order toeffectively remove the copper mist, the deflecting plate 19 formed bybending axially the outside of the annular portion into a cylindricalshape to partly cover the coolant/filter 5 is provided with the annularmember 18 mentioned above. This deflecting plate 19 is formed so as tocover at least the part of the coolant/filter 5 projected horizontallyfrom the gas discharge port 11 in the housing 3, and desirably arrangedbetween the outer periphery of the coolant/filter 5 and the inner wallsurface of the housing 3 to secure a predetermined gap 20 between bothsurfaces. With this structure, the copper mist generated due to thecombustion of the gas generator 8 is cooled during passing through thecoolant/filter 5, and the mist strikes against the deflecting plate 19to be adhered thereto or drop, thereby being removed. The gap 20 formedbetween the outer periphery of the coolant/filter 5 and the inner wallsurface of the housing 3 also functions as the flow-path of theoperating gas.

In order to block entering of a moisture into the housing 3 fromoutside, the gas discharge port 11 of the diffuser shell 1 is closed bythe aluminum tape 15.

In the gas generator structured in the above manner, when a sensor (notshown) detects the impact, the signal thereof is transmitted to theigniter 6 and the igniter 6 is activated, whereby the transfer charge 7is ignited to generate a high-temperature flame. The flame breaks thewall of the aluminum tape 15 to be discharged from the row of throughholes 14, and then enters into the combustion chamber 9 defined by thecoolant/filter 5. The flame entering the combustion chamber 9 ignitesthe gas generating agent 8 near the through holes 14, and is deflectedby the wall portion of the annular member 18 to ignite the gasgenerating agent 8 in the lower portion of the combustion chamber 9.Accordingly, the gas generating agent 8 is burnt so as to generate thegas having a high temperature and a high pressure. The combustion gas(that is, the operating gas) passes through the coolant/filter 5, and,at this time, the gas is cooled in accordance with a cooling function ofthe coolant/filter 5 and the combustion residue is collected inaccordance with a collecting function of the filter, so that the cooledand purified combustion gas (that is, the operating gas) passes throughthe gas flow path (the gap 20) and flows into the air bag (not shown)through the gas discharge port 11. Consequently, the air bag is inflatedto form a cushion between the passenger and a hard structure, therebyprotecting the passenger from the impact.

Embodiment 7—(5) Housing in Which Inlet Port of Igniter also has BentPortion

FIG. 7 is a cross sectional view showing a gas generator for the air bagcomprising a housing for the gas generator in one embodiment inaccordance with the present invention.

The gas generator shown in this drawing comprising, in a housing 3 witha gas discharge port 11, a ignition means including an electric typeigniter 6 and a transfer charge 7, and a gas generating means (that is,a gas generator 8) to generate an operating gas for inflating an air bagupon activation of the ignition means, in which a coolant/filter means(that is, a coolant 5) for cooling the operating gas generated due tothe combustion of the gas generating agent 8 is disposed between acombustion chamber 9 which accommodates the gas generating agent 8 and acircumferential wall portion of the housing 3. Further, a deflectingmember 18 having a tube portion 19 is arranged in the end portion of thecoolant 5 in the diffuser shell 1 side.

The ignition means is stored in an ignition means accommodating chamber10, and the ignition means accommodating chamber 10 is secured in acylindrically formed inner cylindrical member 4 provided with a flangeportion 24 welded to the inner surface of the upper end portion in thehousing 3. The ignition means accommodating chamber 10 can communicatewith the combustion chamber 9 provided outside the cylindrical membervia a plurality of flame-transferring ports 14 formed on acircumferential wall of the inner cylindrical member 4. And, in theinner cylindrical member 4, an igniter 6 constituting the ignition meansis stored in the lower end side thereof, and the end portion thereof iscrimped to fix the igniter 6 in the inner cylindrical member 4. Further,the inner cylindrical member 4 in which the end portion is crimped tofix the igniter 6 is stored in an opening portion 60 of a closure shell2 mentioned below so as not to protrude from the bottom surface of thehousing 3 with the igniter 6 fixed. That is, in this embodiment, theinner cylindrical member 4 functions as an igniter supporting member.

In this embodiment, the housing 3 comprises a diffuser shell 1 formed ina substantially cylindrical shape with a top and having the gasdischarge port, and the closure shell 2 formed in a substantiallycylindrical shape with a bottom and closing the diffuser shell 1. Bothshells can be formed by press-molding a stainless steel.

In the present embodiment, the diffuser shell 1 has a first circularportion 50 forming a ceiling surface (that is, the upper end portion) ofthe housing, an inclining portion 51 inclined downwards to surround thecircular portion 50, a circumferential wall portion 52 descendingperpendicularly to the circular portion from the inclining portion andprovided with a plurality of gas discharge ports 11 along the peripheraldirection, and a flange portion 53 extending radially from thecircumferential wall portion. And on the other hand, the closure shell 2has a second circular portion 54 which forms a bottom surface (that is,the lower end portion) of the housing and is provided with an ignitionmeans receiving hole in the center, an opening portion 60 which isformed at the center of the second circular portion and provided with atubular portion 61 which is bent towards the inside of the housing, acircumferential wall portion 55 which is bent from the peripheral edgeof the second circular portion 54 and inclines as to spread outwardlyand radially, and a flange portion 58 spreading outwardly and radiallyfrom a end of the circumferential wall portion. Both shells obtained inthis manner forms the housing, which is an outer shell of the gasgenerator for an air bag, by joining to each other to be integrated.

In the housing formed in the this manner, the inner cylindrical member 4is inserted to the opening portion 60 formed on the end surface in theclosure shell side, and the inner cylindrical member 4 inserted to theopening portion 60 is welded and fixed near the inlet port of theopening portion. In the opening portion, a connecting portion 62 fixingthe inner cylindrical member 4 with a welding is provided inside of thehousing rather than on the bottom surface of the housing, that is, thebottom surface of the closure shell. In particular, in this embodiment,the periphery of the opening portion 60 is formed so as to be inclinedinside the housing towards the center thereof, thereby setting theconnecting portion 62 of the opening portion inside the housing ratherthan the bottom surface of the housing. Further, the opening portion 60is formed so as to correspond to an outer diameter and a shape of theinner cylindrical member for the purpose of inserting and fixing theinner cylindrical member.

Then, since the opening portion 60 is provided with the tubular portion61 bent inside the housing 3, the inner cylindrical member 4 can befixed more securely. And, since the tubular portion 61 is bent insidethe housing 3, there is never be the case such that only the tubularportion 61 is protruded outside in the axial direction of the housing 3,and therefore, the overall height of the housing 3 itself can berestricted, and thereby, the overall height of the gas generator can berestricted. On the contrary, when the above gas generator is formed tohave the same height as that of the gas generator in which the tubularportion 61 is bent outside the housing 3, the internal capacity of thehousing can be sufficiently increased even it has the same height andouter diameter.

Further, since the tubular portion 61 is bent inside the housing 3, evenin the case of outwardly fitting a substantially annular under plate 22,which supports the gas generating means, to the inner cylindrical member4 and being disposed in the combustion chamber 9 as shown in the presentembodiment, the under plate 22 is supported by the tubular portion 61because the portion inwardly fitting the inner cylindrical member 4contacts with the end of the tubular portion 61.

The gas generator shown in the present embodiment corresponds to a gasgenerator which is preferably arranged in the driver side in particular,and is formed so that an overall height (that is, the axial length) isabout 35 mm. In the gas generator structured in the above manner, thetubular portion 61 provided in the opening portion 60 is formed alongabout 17% of the axial length of the housing so that the axial length isabout 6 mm.

In this housing 3, the circumferential wall portion 55 of the closureshell 2 is inclined towards the circumferential wall portion 52spreading more outwardly and radially than the first circular portion 50because of the inclining portion 51 of the diffuser shell 1, and a bentportion 56 formed between the second circular portion 54 and thecircumferential wall portion 55 in the closure shell 2 is adjusted sothat the interior angle θ becomes between 90 and 135 degrees.

Further, in the present embodiment, the first and second circularportions 50 and 54 are formed so as to have the same size. Accordingly,the coolant 5 disposed in the housing is structured such that the outerperiphery of the upper end surface thereof is supported via thedeflecting member 18 by a bent portion 57 formed between the firstcircular portion 50 and the inclining portion 51 in the diffuser shell1, and the outer periphery of the lower end surface of the coolant 5 isdirectly supported by a bent portion 56 formed between the secondcircular portion 54 and the circumferential wall portion 55 in theclosure shell 2. By supporting the outer peripheries of the upper andlower end surfaces of the coolant 5 by the bent portions 56 and 57formed in the housing in this manner, the coolant is positioned andsupported by the bent portions at a time of arranging the coolant 5.Further, at a time of activation of the gas generator, the coolant 5 ispress-contacted with and supported by the bent portion to block amovement thereof, the upper end portion of the coolant 5 is surroundedby the deflecting member 18 so as to be adhered to the bent portion 57of the diffuser shell 1, and the outer peripheral edge of the lower endportion of the coolant 5 is directly adhered to the bent portion 56 ofthe closure shell 2 so as to prevent the operating gas from passingbetween the inner surface of the housing and the coolant 5 (that is, theshort pass).

In this case, at a time of forming the housing, it is possible to form arib-like reinforcing member and/or a reinforcing step portion in both oreither of the first circular portion 50 of the diffuser shell and thesecond circular portion 54 of the closure shell so as to improve thestrength of the housing.

The coolant 5 disposed in the housing is preferably structured such asnot to expand outwardly and radially by a pressure caused when theoperating gas passes through. This is because, in the case that thecoolant 5 is expanded out due to passage of the gas generating means, agap 20 secured between the coolant 5 and the inner periphery of thehousing is closed and can not function as the gas flow-path.Accordingly, the coolant 5 shown in this embodiment is formed so that atensile strength in the radial direction is 12054 N (1230 kgf).

The deflecting member 18 is useful in the case of using the gasgenerating agent 8 to generate the combustion product in a fluidizedstate or a semi-fluidized state due to the combustion. That is, thecombustion product generated due to the combustion of the gas generatingagent cab be removed by adhering the combustion product to the tubeportion 19 of the deflecting member 18 or by allowing the product tostrike thereagainst to drop. Further, since the annular portion 16contacting with the end surface of the coolant 5 in the deflectingmember 18 is formed to have a suitable elasticity, a wire mesh coolant 5less elasticated in the axial direction can be used as the coolant 5disposed outside in the radial direction of the combustion chamber 9.Further, in the deflecting member 18, the wall portion 17 contactingwith the inner periphery of the coolant 5 is integrally formed with theannular portion 16. With this structure, it is possible to position andfix the coolant 5 and a so-called short pass that the operating gas isdischarged without passing through the coolant can be inhibited.

In the gas generator formed in the above manner, the transfer charge 7is ignited and burnt by the igniter 6 activated upon the activatingsignal, and the flame thereof is discharged into an accommodating spaceof the gas generating agent 8 through a flame-transferring port 14 ofthe inner cylindrical member 4. The flame of the transfer charge 7ignites and burns the gas generating agent 8, and even in the case thata part thereof directly passes through the coolant 5, it strikes againstthe tube portion 19 of the deflection member 18, and thereby the flameis prevented from directly being discharged through the gas dischargeport 11. The operating gas which is generated by the gas generatingagent 8 ignited by the flame of the transfer charge 7 passes through thecoolant 5 and reaches inside the gap 20 secured between the outerperiphery of the coolant 5 and the inner periphery of the housing 3. Inthe case that the combustion product in a fluidized state or asemi-fluidized state is contained in the operating gas after passingthrough the coolant 5, the combustion product strikes against or isadhered to the tube portion 19 of the deflecting member 18 arranged inthe gap 20 so as to be removed from the operating gas.

In FIG. 7, the gas discharge port 11 and the flame-transferring port 14are respectively closed by seal tapes 15, and the gas generating agent 8is supported by the under plate 22 and is stored in the combustionchamber. Further, the member described as the deflecting member 18 inthe present embodiment can function as a mist collecting member or aflame preventing plate in the same structure.

Embodiment 8 Air Bag Apparatus

The gas generator for the air bag mentioned above is stored within amodule case together with an air bag (bag body) to introduce a gasgenerated in the gas generator and inflate, thereby forming an air bagapparatus.

The air bag apparatus discharges the combustion gas from a gas dischargeport of the housing when the gas generator is activated, reacting uponan impact sensor detecting the impact. The combustion gas flows into theair bag, whereby the air bag breaks the module cover so as to inflate,thereby forming a cushion absorbing the impact between a hard structurein the vehicle and a passenger.

FIG. 8 shows an embodiment of the air bag apparatus including a gasgenerator using an electric ignition type ignition means.

The air bag apparatus comprises a gas generator 200, an impact sensor201, a control unit 202, a module case 203 and an air bag 204. The gasgenerator 200 employs the gas generator described on the basis of anyone of FIGS. 1, 4, 5 and 7, and the activation performance thereof isadjusted so as not to apply as small impact to a passenger as possibleat the initial stage of the activation of the gas generator.

The impact sensor 201 may comprise, for example, a semiconductor typeacceleration sensor. The semiconductor type acceleration sensor isstructured such that four semiconductor strain gauges are formed on abeam of a silicon plate to defect when an acceleration is applied, andthese semiconductor strain gauges are bridge connected. When theacceleration is applied, the beam defects and the strain is produced onthe surface. Due to this strain, a resistance of the semiconductorstrain gauge is changed, and the resistance change is detected as avoltage signal in proportion to the accelerator.

The control unit 202 is provided with an ignition judging circuit, andis structured such that the signal from the semiconductor typeacceleration sensor is inputted to the ignition judging circuit. Thecontrol unit 202 starts calculating at a time when the impact signaloutputted from the sensor 201, and outputs the activating signal to theigniter 5 or 104 of the gas generator 200 when the calculated resultexceeds a certain value.

The module case 203 is formed, for example, by a polyurethane, andincludes a module cover 205. The air bag 204 and the gas generator 200are stored in the module case 203 so as to constitute a pad module. Thepad module is generally mounted to a steering wheel 207 in the case ofbeing mounted to the driver side of automobiles.

The air bag 204 is formed by a nylon (for example, a nylon 66), apolyester or the like, a bag port 206 thereof surrounds the gasdischarge port of the gas generator, and the air bag is fixed to theannular portion of the gas generator in a folded state.

When the semiconductor type acceleration sensor 201 detects the impactat a time when the motor vehicle is collided, the signal is transmittedto the control unit 202, and the control unit 202 starts calculatingwhen the impact signal outputted from the sensor exceeds a certainvalue. When the calculated result exceeds a certain value, the controlunit 202 outputs the activating signal to the igniter 6 of the gasgenerator 200. Accordingly, the igniter 6 or 104 is activated to ignitethe gas generating agent, and the gas generating agent burns andgenerates a gas. The gas is injected out into the air bag 204, andthereby the air bag breaks the module cover 205 so as to inflate andforms a cushion absorbing the impact between the steering wheel 207 anda passenger.

1. A deflecting member of a gas generator for an air bag, which is aconstituting member used in a gas generator for an air bag comprising,in a cylindrical housing with a gas discharge port, a gas generatingmeans to generate an operating gas for inflating an air bag and acylindrical coolant/filter means to cool and/or purify the operating gasin the housing, wherein a tube portion has a shape capable of beingarranged to face an inner periphery of the cylindrical gas generatorhousing, and the tube portion is formed in a shape and/or a structurecapable of shielding at least a gas discharge port formed in acircumferential wall of the gas-generator housing from the inside of thehousing, and the deflecting member is formed to have a shape and/or astructure capable of preventing a combustion product generated due to acombustion of the gas generating means from being discharged out of thehousing through the gas discharge port.
 2. A deflecting member asclaimed in claim 1, wherein the deflecting member includes the tubeportion which is formed to shield a gas discharge port formed in acircumferential wall of the gas-generator housing from the inside of thehousing, and an inwardly flange-shaped annular portion, which is formedto contact with either end surface of the coolant/filter means.
 3. Adeflecting member as claimed in claim 1, wherein the tube portion isformed to cover the part of the coolant/filter means projectedhorizontally from a gas discharge port.
 4. A deflecting member asclaimed in claim 1, wherein the tube portion is formed in the housing ofthe gas generator to secure a flow-path of the operating gas between thetube portion and the coolant/filter means and between the tube portionand the inner surface of the housing.
 5. A deflecting member as claimedin claim 1, wherein the tube portion is formed so that an inner diameterof the upper portion thereof has the same size as an outer diameter ofthe coolant/filter means, and inner diameters of the middle portion andthe lower portion thereof are larger than the inner diameter of theupper portion.
 6. A deflecting member as claimed in claim 1, wherein thetube portion is structured such that a supporting portion with an endbent outwardly and radially is formed in at least one end portion in theaxial direction.
 7. A deflecting member as claimed in claim 6, whereinthe supporting portion is formed to contact with an inner periphery ofthe housing and support the tube portion.
 8. A deflecting member asclaimed in claim 6, wherein a ventilating portion capable of passing theoperating gas is formed in the supporting portion.
 9. A deflectingmember as claimed in claim 1, wherein the deflecting member is formed tohave a shape and/or a structure capable of preventing a flame of theignition means for igniting the gas generating means and/or a flamegenerated by combustion of the gas generating means from beingdischarged out of the housing through the gas discharge port.
 10. Adeflecting member as claimed in claim 1, wherein the deflecting memberis provided with an inwardly flange-shaped annular portion, formed tocontact with either end surface of the coolant/filter means, and acentral opening of the annular portion is formed so that an inner edgeend surface thereof has a size to contact with an end surface of aninner cylindrical member disposed in the housing of the gas generator.11. A deflecting member as claimed in claim 1, wherein the deflectingmember is provided with the inwardly flange-shaped annular portion,formed to contact with either end of the coolant/filter means, the tubeportion is formed to be connected to an outer peripheral edge of theannular portion, and a bent portion between the tube portion and theannular portion is formed to have a shape and/or a structure capable ofpositioning the coolant/filter means and/or preventing the operating gasfrom passing between the end surface of the coolant/filter means and theinner periphery of the housing at a time of activating the gasgenerator.
 12. A deflecting member as claimed in claim 1, wherein thedeflecting member is provided with the inwardly flange-shaped annularportion, formed to contact with either end surface of the coolant/filtermeans, and a wall portion in a shape contacting with the inner peripheryof the coolant/filter means is formed in the annular portion.
 13. Adeflecting member as claimed in claim 12, wherein the wall portion isformed to have a shape and/or a structure capable of positioning thecoolant/filter means and/or preventing the operating gas from passingbetween the end surface of the coolant/filter means and the innerperiphery of the housing at a time of activating the gas generator. 14.A deflecting member as claimed in claim 12, wherein the wall portion isformed so that a width between the wall portion and the tube portionbecomes a thickness of the coolant/filter means disposed in the housingof the gas generator.
 15. A deflecting member as claimed in claim 1,wherein the deflecting member is formed as a single member.
 16. A gasgenerator for an air bag comprising; in a cylindrical housing with a gasdischarge port, an ignition means to activate a gas generator; a gasgenerating means to generate an operating gas for inflating an air bagupon an activation of the ignition means; and a cylindricalcoolant/filter means to purify and/or cool the operating gas; wherein aspace portion forming a flow-path of the operating gas is securedbetween an outer periphery of the cylindrical coolant/filter means andan inner periphery of a circumferential wall portion of the housing, anda deflecting member having a shape and/or a structure capable ofdeflecting a flow of the operating gas passing through thecoolant/filter means towards the gas discharge port, the deflectingmember being formed to have a shape and/or a structure capable ofpreventing a combustion product generated due to a combustion of the gasgenerating means from being discharged out of the housing through thegas discharge port, and a mist collecting member for collecting and/orremoving a combustion by-product contained in the operating gas arearranged in the space portion.
 17. A gas generator for an air bag asclaimed in claim 16, wherein the deflecting member contacts with eitherend surface of the cylindrical coolant/filter means.
 18. A gas generatorfor an air bag as claimed in claim 16, wherein the space forming theflow-path of the operating gas is secured between the outer periphery ofthe cylindrical coolant/filter means and the inner periphery of thecircumferential wall portion of the housing, and a part of thedeflecting member is arranged in the space portion so as to deflect aflow of the operating gas passing through the coolant/filter meanstowards the gas discharge port.
 19. A gas generator for an air bag asclaimed in claim 16, wherein the deflecting member has a portion whichcontacts with neither the coolant/filter means nor the inner peripheryof the housing in the space portion secured between the outer peripheryof the cylindrical coolant/filter means and the inner periphery of thecircumferential wall portion of the housing.
 20. A gas generator for anair bag as claimed in any one of claims 16 to 22, wherein thecoolant/filter means is positioned and/or supported by the deflectingmember, and the position thereof is not shifted even by the combustionpressure of the gas generating means.
 21. A gas generator for an air bagcomprising: an ignition means to activate a gas generator; in acylindrical housing having a gas discharge port, a gas generating meansto generate an operating gas for inflating an air bag upon an activationof the ignition means; a deflecting member formed to have a shape and/ora structure capable of preventing a combustion product generated due toa combustion of the gas generating means from being discharged out ofthe housing through the gas discharge port; and a cylindricalcoolant/filter means to purify and/or cool the operating gas; wherein aspace portion forming a flow-path of the operating gas is securedbetween an outer periphery of the cylindrical coolant/filter means andan inner periphery of a circumferential wall portion of the housing, anda mist collecting member for collecting and/or removing a combustionby-product contained in the operating gas is arranged in the spaceportion.
 22. A gas generator for an air bag comprising: in a cylindricalhousing having a gas discharge port, an ignition means to activate a gasgenerator; a gas generating means to generate an operating gas forinflating an air bag upon an activation of the ignition means; and acylindrical coolant/filter means to purify and/or cool the operatinggas; wherein a space portion forming a flow-path of the operating gas issecured between an outer periphery of the cylindrical coolant/filtermeans and an inner periphery of a circumferential wall portion of thehousing, a deflecting member is formed to have a shape and/or astructure capable of preventing a combustion product generated due to acombustion of the gas generating means from being discharged out of thehousing through the gas discharge port, and a flame preventing plate anda mist collecting member for collecting and/or removing a combustionby-product contained in the operating gas are arranged in the spaceportion.
 23. A gas generator for an air bag comprising: in a cylindricalhousing having a gas discharge port, an ignition means to activate a gasgenerator; a gas generating means to generate an operating gas forinflating an air bag upon an activation of the ignition means; and acylindrical coolant/filter means to purify and/or cool the operatinggas; wherein the deflecting member as claimed in any one of claims 1 to8 and 10 to 16 is arranged in the vicinity of the cylindricalcoolant/filter means.
 24. A gas generator for an air bag as claimed inclaim 23, wherein the deflecting member brings the annular portion intocontact with the end surface of the coolant/filter means and partlycovers the outer periphery of the coolant/filter means with the tubeportion in the axial direction.
 25. A gas generator for an air bagcomprising: in a cylindrical housing having a gas discharge port, anignition means to activate a gas generator; a gas generating means togenerate an operating gas for inflating an air bag upon an activation ofthe ignition means; and a cylindrical coolant/filter means to purifyand/or cool the operating gas; wherein a coolant/filter means supportingmember formed in a single member is disposed in the vicinity of thecylindrical coolant/filter means to prevent the operating gas frompassing between an end surface of the coolant/filter means and an innerperiphery of the housing and/or to position the coolant/filter means,and/or to prevent the heat from being transferred from thecoolant/filter means to the housing and/or to support the coolant/filtermeans between the upper and lower inner surfaces of the housing due toan elasticity, and wherein a deflecting member is formed to have a shapeand/or a structure capable of preventing a combustion product generateddue to a combustion of the gas generating means from being dischargedout of the housing through a gas discharge port.
 26. A gas generator foran air bag comprising: in a cylindrical housing with a gas dischargeport, a gas generating means to generate an operating gas for inflatingan air bag; and a cylindrical coolant means to cool and/or purify theoperating gas in a cylindrical housing having a gas discharge port;wherein an outer peripheral edge of an end portion in the coolant meansis adhered and/or supported to a bent portion or a step portion formedon an inner surface of the upper end portion and/or an inner surface ofthe lower end portion of the cylindrical housing, at a time ofassembling the gas generator and/or at a time of activating the gasgenerator, and wherein a deflecting member is formed to have a shapeand/or a structure capable of preventing a combustion product generateddue to a combustion of the gas generating means from being dischargedout of the housing through the gas discharge port.